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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water .
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how did earth get food and water ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
|
thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension .
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what does hank mean by surface tension ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion .
|
so h2o on the wax seemed to stick together better then on the glass surface ... is that true , that depending on the elements , h2o ( for example ) can have its cohesion to itself lessened due to adhesion ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water .
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how did earth get so much water ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ?
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where did the first sub-atomic particle come from ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
|
scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars .
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did scientist find what they believe is water on on of the planets recently ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge .
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why is the water molecule v-shaped ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks .
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why dose salt sink after it is steered after about 5 minutes ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish .
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is what hank was reading `` a short history of nearly everything '' ?
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man in glasses : hello , there . here at crash course hq we like to start out each day with a nice healthy dose of water in all its 3 forms . it 's the only substance on all of our planet earth that occurs naturally in solid , liquid and gas forms . to celebrate this magical bond between two hydrogen atoms and one oxygen atom , here today we are going to be celebrating the wonderful life-sustaining properties of water , but we 're going to do it slightly more clothed . ( boppy music ) ah , much better . when we left off here at the biology crash course we were talking about life , and the rather important fact that all life as we know it is dependent upon there being water around . scientists and astronomers are always looking out into the universe trying to figure out whether there is life elsewhere because that is kind of the most important question that we have right now . they 're always getting really excited when they find water someplace , particularly liquid water . this is one reason why i and so many other people geeked out so hard last december when mars ' seven-year-old rover opportunity found a 20-inch long vein of gypsum that was almost certainly deposited by long term liquid water on the surface of mars . this was probably billions of years ago , and so it 's going to be hard to tell whether or not the water that was there resulted in some life . maybe we can figure that out and that would be really exciting . why ? why do we think that water is necessary for life ? why does water on other planets get us so freaking excited ? let 's start out by investigating some of the amazing properties of water . in order to do that , we 're going to have to start out with this . the world 's most popular molecule , or at least the world 's most memorized molecule . we all know about it . good old h20 . two hydrogens , one oxygen , the hydrogens each sharing an electron with oxygen in what we call a covalent bond . as you can see , i 've drawn my water molecule in a particular way . this is actually the way that it appears . it is v-shaped . because this big old oxygen atom is a little bit more greedy for electrons , it has a slight negative charge ; whereas , this area here with the hydrogen atoms has a slight positive charge . thanks to this polarity , all water molecules are attracted to one another ; so much so that they actually stick together and these are called hydrogen bonds . we talked about them last time , but essentially what happens is that the positive pole around those hydrogen atoms bonds to the negative pole around the oxygen atoms of a different water molecule . it 's a weak bond , but look , they 're bonding ! seriously , i can not overstate the importance of this hydrogen bond . when your teacher asks you , `` what 's important about water ? '' start out with the hydrogen bonds and you should put it in all caps and maybe some sparkles around it . one of the cool properties that results from these hydrogen bonds is a high cohesion for water which results in high surface tension . cohesion is the attraction between two like things , like attraction between one molecule of water and another molecule of water . water has the highest cohesion of any nonmetalic liquid . you can see this if you put some water on some wax paper or some teflon or something where the water beads up like this . some leaves of plants do it really well ; it 's quite cool . since water adheres weakly to the wax paper or to the plant , but strongly to itself , the water molecules are holding those droplets together in a configuration that creates the least amount of surface area . this is high surface tension that allows some bugs and even i think one lizard and also one jesus to be able to walk on water . the cohesive force of water does have its limits , of course . there are other substances that water quite likes to stick to . take glass , for example . this is called adhesion . the water is spreading out here instead of beading up because the adhesive forces between the water and the glass are stronger than the cohesive forces of the individual water molecules in the bead of water . adhesion is attraction between two different substances , so in this case the water molecules and the glass molecules . these properties lead to one of my favorite things about water ; the fact that it can defy gravity . that really cool thing that just happened is called capillary action . explaining it can be easily done with what we now know about cohesion and adhesion . thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion . the surface tension created here causes the water to climb up the straw . it will continue to climb until eventually gravity pulling down on the weight of the water in the straw overpowers the surface tension . the fact that water 's a polar molecule also makes it really good at dissolving things , which we call it 's a good solvent then . scratch that . water is n't a good solvent . it 's an amazing solvent . there are more substances that can be dissolved in water than in any other liquid on earth . yes , that includes the strongest acid that we have ever created . these substances that dissolve in water , sugar or salt being ones that we 're familiar with , are called hydrophilic , and they are hydrophilic because they are polar . their polarity is stronger than the cohesive forces of the water . when you get one of these polar substances in water , it 's strong enough that it breaks all the little cohesive forces , all those little hydrogen bonds . instead of hydrogen bonding to each other , the water will hydrogen bond around these polar substances . table salt is ionic , and right now it 's being separated into ions as the poles of our water molecules interact with it . what happens when there is a molecule that can not break the cohesive forces of water ? it ca n't penetrate and come into it . basically , what happens when that substance ca n't overcome the strong cohesive forces of water , ca n't get inside of the water ? that 's when we get what we call a hydrophobic substance , or something that is fearful of water . these molecules lack charged poles . they are non-polar and are not dissolving in water because essentially they 're being pushed out of the water by water 's cohesive forces . water , we may call it the universal solvent , but that does not mean that it dissolves everything . ( boppy music ) there have been a lot of eccentric scientists throughout history , but all this talk about water got me thinking about perhaps the most eccentric of the eccentrics , a man named henry cavendish . he communicated with his female servants only via notes , and added a staircase to the back of his house to avoid contact with his housekeeper . some believe he may have suffered from a form of autism , but just about everyone will admit that he was a scientific genius . he 's best remembered as the first person to recognize hydrogen gas as a distinct substance and to determine the composition of water . in the 1700s , most people thought that water itself was an element , but cavendish observed that hydrogen , which he called inflammable air , reacted with oxygen , known then by the awesome name , dephlogisticated air , to form water . cavendish did n't totally understand what he 'd discovered here , in part because he did n't believe in chemical compounds . he explained his experiments with hydrogen in terms of a fire-like element called phlagiston . nevertheless , his experiments were groundbreaking . like his work in determining the specific gravity basically the comparative density of hydrogen and other gases with reference to common air . it 's especially impressive when you consider the crude instruments he was working with . this , for example , is what he made his hydrogen gas with . he went on not only to establish an accurate composition of the atmosphere , but also discovered the density of the earth . not bad for a guy who was so painfully shy that the only existing portrait of him was sketched without his knowledge . for all of his decades of experiments , cavendish only published about 20 papers . in the years after his death , researchers figured out that cavendish had actually pre-discovered richter 's law , ohm 's law , coulomb 's law , several other laws . that 's a lot of freaking laws . if he had gotten credit for them all , we would have had to deal with like cavendish 's 8th law and cavendish 's 4th law , so i , for one , am glad that he did n't actually get credit . we 're going to do some pretty amazing science right now . you guys are not going to believe this . okay , you ready ? it floats ! yeah , i know you 're not surprised by this , but you should be because everything else , when it 's solid is much more dense than when it 's liquid ; just like gases are much less dense than liquids are . but that simple characteristic of water that its solid form floats is one of the reasons why life on this planet , as we know it , is possible . why is it that solid water is less dense than liquid water while everything else is the exact opposite of that ? well , you can thank your hydrogen bonds once again . at around 32 degrees fahrenheit or 0 degrees celsius if you 're a scientist or from a part of the world where things make sense , water molecules start to solidify and the hydrogen bonds in those water molecules form crystalline structures that space molecules apart more evenly , in turn making frozen water less dense than its liquid form . so in almost every circumstance a floating water ice is a really good thing . if ice were denser than water it would freeze and then sink , and then freeze and then sink , and then freeze and then sink , so just trust me on this one . you do n't want to live on a world where ice sinks . not only would it totally wreak havoc on aquatic eco systems which are basically how life formed on the earth in the first place . also , all the ice in the north pole would sink and then all of the water everywhere else would rise and we would n't have any land . that would be annoying . there 's one more amazing property of water i 'm forgetting . why is it so hot in here ? heat capacity ! yes , water has a very high heat capacity and probably that means nothing to you . basically it means that water is really good at holding on to heat , which is why we like to put hot water bottles in our bed and cuddle with them when we 're lonely . aside from artificially warming your bed , it 's also very important that it 's hard to heat up and cool down the oceans significantly . they become giant heat sinks that regulate the temperature and the climate of our planet , which is why , for example , it 's so much nicer in los angeles where the ocean is constantly keeping the temperatures the same than it is in , say , nebraska . on a smaller scale , we can see water 's high heat capacity really easily and visually by putting a pot with no water in it on a stove and seeing how badly that goes . but then you put a little bit of water in it and it takes forever to freaking boil ! and if you have n't already noticed this , when water evaporates from your skin , it cools you down . that 's the principle behind sweating , which is an extremely effective , though somewhat embarrassing , part of life . this is an example of another incredibly cool thing about water . when my body gets hot and it sweats , that heat excites some of the water molecules on my skin to the point where they break those hydrogen bonds and they evaporate away . when they escape , they take that heat energy with them , leaving me cooler . lovely . this was n't exercise , though . i do n't know why i 'm sweating so much . it could be the spray bottle that i keep spraying myself with , or maybe it 's just because this is such a high stress enterprise trying to teach you people things .
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thanks to adhesion , the water molecules are attracted to the molecules in the straw . as the water molecules adhere to the straw , other molecules are drawn in by cohesion following those fellow water molecules . thank you cohesion .
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do you think that mars had the same molecules in its water as earth does ?
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steven zucker : dionysus , the god of wine , did n't like to be lonely . he was surrounded by satyrs and by maenads . he loved to party . beth harris : and you ca n't party alone . steven zucker : no , you ca n't party alone . and of course , those satyrs would become tired sometimes , after they drank a bit too much . and that 's exactly the subject of the barberini faun that we 're looking at . beth harris : now , a satyr is not a human being . he may look human to us , but he 's , in greek mythology , part animal , really . steven zucker : that 's right . he 's a subhuman . the hierarchy of the gods were the gods of mount olympus at the top . then you had heroes that were half divine and half human . then you had humans . and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves . beth harris : yeah , you can see the tail actually coming from behind his left thigh . that 's where i first noticed it . steven zucker : and for the greeks , these particular subhumans , the satyrs , were half civilized and half wild . and so it was a wonderful way to express the uncultivated , the kind of barbaric qualities of human nature . beth harris : his name is the barberini faun . he 's not really a faun . he 's really more a satyr . but he 's called the barberini faun because when he was discovered in rome , near the castel sant'angelo in 1625 , the pope at the time was from the barberini family . and everyone recognized how spectacular this figure was . and the pope said , well , i officially declare this to be part of my family collection . steven zucker : he wanted to do that because it was so important , not only as just a stellar example of sculpture , but we think that this actually dates to the third century bce . and that it is an original greek sculpture . beth harris : although it 's always very hard to tell whether something is a greek original or a later roman copy . steven zucker : it could be a terrific copy . we do know , though , that at least a portion of it has been restored . and you can see those restorations quite clearly in the lower part of the left thigh and almost the entire right leg and foot . beth harris : so this spectacular sculpture ended up here in munich when it was acquired by prince ludwig of bavaria in the early 19th century . quite a sculpture to add to his collection for his new museum . steven zucker : it 's an amazing thing to think that this was likely found in the moat of hadrian 's tomb in what is now castel sant'angelo in rome . i imagine people were vying to purchase this . beth harris : it 's incredibly erotic . this figure has his legs spread . he 's in a drunken , half sleeping , half awake state . steven zucker : we can see that in his body . on the one hand , it 's absolute exhaustion . he is just dead tired . but on the other side , you can see the agitation of his body . there 's tension there . look at that right leg , the way it 's pushed up . now , that part is a restoration . but we know that that 's pretty much the placement because of the rock on which it sat . beth harris : and you can see from his face , too , that there 's a combination of exhaustion and restlessness . steven zucker : well , look at that face . it is just spectacularly sensitive . and i love the fact that it 's not symmetrical . his head is pushed over to the side . and if you look at his cheek straight on , you can see that gravity is compressing the right side of his face and it 's expanding the left side . and so there really is this intense naturalism , this observation of the elastic qualities of the human body . beth harris : now , we 're in the hellenistic period , where ancient greek artists are expanding their subject matter . so we do n't just have the heroic , ideal , athletic nudes that we saw in the classical period . but here , the art is exploring more emotional states , more varieties of subject matter . steven zucker : that 's right . sometimes this is even referred to as the hellenistic baroque , because of its willingness to remove the reserve that we associate with the high classical period before . beth harris : he 's certainly not reserved in any way . steven zucker : no , not at all . so what are the other accoutrements ? what are the other symbols that identify him as a satyr ? as if the tail and the ears and the wanton abandon quality was n't enough , you can see that he 's laid out a leopard skin . he 's on a rock , and it 's certainly protecting him from the roughness of the rock . and you can see that he 's even keeping his heel on it . it 's softer , and he 's rolled it up a little bit under his arm so that it functions somewhat like a cushion . beth harris : although it is a little bit hard for you to imagine him walking up to this rock , laying down the leopard skin , and then somehow lying on it . steven zucker : no , it 's a conceit . beth harris : it is . steven zucker : so you said that this is hellenistic , and it certainly is , in so many ways . but it is clearly informed by the classical tradition that had come before it . beth harris : in terms of its treatment of the human body and its attention to musculature and anatomy . steven zucker : absolutely . and i think that 's really clear in the torso . beth harris : we can see the folds of his flesh in his abdomen , or the careful articulation of the muscles in the shoulders and the armpit . this is an amazing understanding of human anatomy . steven zucker : but it is also a little bit off-kilter . you can see that the ribcage is pushing a little bit to his left . and so the whole thing has a gentle turn to it , making it even more complex . beth harris : there is a turn in the torso , and we see that in other ancient greek sculptures , like the belvedere torso . and although this was found 100 years after michelangelo , or a little bit less , you can see how that kind of twisting and torsion in the body was something that michelangelo would pick up on . steven zucker : i think if michelangelo had ever had the opportunity to see this , he would have absolutely loved it . beth harris : no question .
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it 's softer , and he 's rolled it up a little bit under his arm so that it functions somewhat like a cushion . beth harris : although it is a little bit hard for you to imagine him walking up to this rock , laying down the leopard skin , and then somehow lying on it . steven zucker : no , it 's a conceit .
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how do we know it is a leopard skin ?
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steven zucker : dionysus , the god of wine , did n't like to be lonely . he was surrounded by satyrs and by maenads . he loved to party . beth harris : and you ca n't party alone . steven zucker : no , you ca n't party alone . and of course , those satyrs would become tired sometimes , after they drank a bit too much . and that 's exactly the subject of the barberini faun that we 're looking at . beth harris : now , a satyr is not a human being . he may look human to us , but he 's , in greek mythology , part animal , really . steven zucker : that 's right . he 's a subhuman . the hierarchy of the gods were the gods of mount olympus at the top . then you had heroes that were half divine and half human . then you had humans . and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves . beth harris : yeah , you can see the tail actually coming from behind his left thigh . that 's where i first noticed it . steven zucker : and for the greeks , these particular subhumans , the satyrs , were half civilized and half wild . and so it was a wonderful way to express the uncultivated , the kind of barbaric qualities of human nature . beth harris : his name is the barberini faun . he 's not really a faun . he 's really more a satyr . but he 's called the barberini faun because when he was discovered in rome , near the castel sant'angelo in 1625 , the pope at the time was from the barberini family . and everyone recognized how spectacular this figure was . and the pope said , well , i officially declare this to be part of my family collection . steven zucker : he wanted to do that because it was so important , not only as just a stellar example of sculpture , but we think that this actually dates to the third century bce . and that it is an original greek sculpture . beth harris : although it 's always very hard to tell whether something is a greek original or a later roman copy . steven zucker : it could be a terrific copy . we do know , though , that at least a portion of it has been restored . and you can see those restorations quite clearly in the lower part of the left thigh and almost the entire right leg and foot . beth harris : so this spectacular sculpture ended up here in munich when it was acquired by prince ludwig of bavaria in the early 19th century . quite a sculpture to add to his collection for his new museum . steven zucker : it 's an amazing thing to think that this was likely found in the moat of hadrian 's tomb in what is now castel sant'angelo in rome . i imagine people were vying to purchase this . beth harris : it 's incredibly erotic . this figure has his legs spread . he 's in a drunken , half sleeping , half awake state . steven zucker : we can see that in his body . on the one hand , it 's absolute exhaustion . he is just dead tired . but on the other side , you can see the agitation of his body . there 's tension there . look at that right leg , the way it 's pushed up . now , that part is a restoration . but we know that that 's pretty much the placement because of the rock on which it sat . beth harris : and you can see from his face , too , that there 's a combination of exhaustion and restlessness . steven zucker : well , look at that face . it is just spectacularly sensitive . and i love the fact that it 's not symmetrical . his head is pushed over to the side . and if you look at his cheek straight on , you can see that gravity is compressing the right side of his face and it 's expanding the left side . and so there really is this intense naturalism , this observation of the elastic qualities of the human body . beth harris : now , we 're in the hellenistic period , where ancient greek artists are expanding their subject matter . so we do n't just have the heroic , ideal , athletic nudes that we saw in the classical period . but here , the art is exploring more emotional states , more varieties of subject matter . steven zucker : that 's right . sometimes this is even referred to as the hellenistic baroque , because of its willingness to remove the reserve that we associate with the high classical period before . beth harris : he 's certainly not reserved in any way . steven zucker : no , not at all . so what are the other accoutrements ? what are the other symbols that identify him as a satyr ? as if the tail and the ears and the wanton abandon quality was n't enough , you can see that he 's laid out a leopard skin . he 's on a rock , and it 's certainly protecting him from the roughness of the rock . and you can see that he 's even keeping his heel on it . it 's softer , and he 's rolled it up a little bit under his arm so that it functions somewhat like a cushion . beth harris : although it is a little bit hard for you to imagine him walking up to this rock , laying down the leopard skin , and then somehow lying on it . steven zucker : no , it 's a conceit . beth harris : it is . steven zucker : so you said that this is hellenistic , and it certainly is , in so many ways . but it is clearly informed by the classical tradition that had come before it . beth harris : in terms of its treatment of the human body and its attention to musculature and anatomy . steven zucker : absolutely . and i think that 's really clear in the torso . beth harris : we can see the folds of his flesh in his abdomen , or the careful articulation of the muscles in the shoulders and the armpit . this is an amazing understanding of human anatomy . steven zucker : but it is also a little bit off-kilter . you can see that the ribcage is pushing a little bit to his left . and so the whole thing has a gentle turn to it , making it even more complex . beth harris : there is a turn in the torso , and we see that in other ancient greek sculptures , like the belvedere torso . and although this was found 100 years after michelangelo , or a little bit less , you can see how that kind of twisting and torsion in the body was something that michelangelo would pick up on . steven zucker : i think if michelangelo had ever had the opportunity to see this , he would have absolutely loved it . beth harris : no question .
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and so the whole thing has a gentle turn to it , making it even more complex . beth harris : there is a turn in the torso , and we see that in other ancient greek sculptures , like the belvedere torso . and although this was found 100 years after michelangelo , or a little bit less , you can see how that kind of twisting and torsion in the body was something that michelangelo would pick up on .
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what was the model for the faces of greek sculptures ?
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steven zucker : dionysus , the god of wine , did n't like to be lonely . he was surrounded by satyrs and by maenads . he loved to party . beth harris : and you ca n't party alone . steven zucker : no , you ca n't party alone . and of course , those satyrs would become tired sometimes , after they drank a bit too much . and that 's exactly the subject of the barberini faun that we 're looking at . beth harris : now , a satyr is not a human being . he may look human to us , but he 's , in greek mythology , part animal , really . steven zucker : that 's right . he 's a subhuman . the hierarchy of the gods were the gods of mount olympus at the top . then you had heroes that were half divine and half human . then you had humans . and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves . beth harris : yeah , you can see the tail actually coming from behind his left thigh . that 's where i first noticed it . steven zucker : and for the greeks , these particular subhumans , the satyrs , were half civilized and half wild . and so it was a wonderful way to express the uncultivated , the kind of barbaric qualities of human nature . beth harris : his name is the barberini faun . he 's not really a faun . he 's really more a satyr . but he 's called the barberini faun because when he was discovered in rome , near the castel sant'angelo in 1625 , the pope at the time was from the barberini family . and everyone recognized how spectacular this figure was . and the pope said , well , i officially declare this to be part of my family collection . steven zucker : he wanted to do that because it was so important , not only as just a stellar example of sculpture , but we think that this actually dates to the third century bce . and that it is an original greek sculpture . beth harris : although it 's always very hard to tell whether something is a greek original or a later roman copy . steven zucker : it could be a terrific copy . we do know , though , that at least a portion of it has been restored . and you can see those restorations quite clearly in the lower part of the left thigh and almost the entire right leg and foot . beth harris : so this spectacular sculpture ended up here in munich when it was acquired by prince ludwig of bavaria in the early 19th century . quite a sculpture to add to his collection for his new museum . steven zucker : it 's an amazing thing to think that this was likely found in the moat of hadrian 's tomb in what is now castel sant'angelo in rome . i imagine people were vying to purchase this . beth harris : it 's incredibly erotic . this figure has his legs spread . he 's in a drunken , half sleeping , half awake state . steven zucker : we can see that in his body . on the one hand , it 's absolute exhaustion . he is just dead tired . but on the other side , you can see the agitation of his body . there 's tension there . look at that right leg , the way it 's pushed up . now , that part is a restoration . but we know that that 's pretty much the placement because of the rock on which it sat . beth harris : and you can see from his face , too , that there 's a combination of exhaustion and restlessness . steven zucker : well , look at that face . it is just spectacularly sensitive . and i love the fact that it 's not symmetrical . his head is pushed over to the side . and if you look at his cheek straight on , you can see that gravity is compressing the right side of his face and it 's expanding the left side . and so there really is this intense naturalism , this observation of the elastic qualities of the human body . beth harris : now , we 're in the hellenistic period , where ancient greek artists are expanding their subject matter . so we do n't just have the heroic , ideal , athletic nudes that we saw in the classical period . but here , the art is exploring more emotional states , more varieties of subject matter . steven zucker : that 's right . sometimes this is even referred to as the hellenistic baroque , because of its willingness to remove the reserve that we associate with the high classical period before . beth harris : he 's certainly not reserved in any way . steven zucker : no , not at all . so what are the other accoutrements ? what are the other symbols that identify him as a satyr ? as if the tail and the ears and the wanton abandon quality was n't enough , you can see that he 's laid out a leopard skin . he 's on a rock , and it 's certainly protecting him from the roughness of the rock . and you can see that he 's even keeping his heel on it . it 's softer , and he 's rolled it up a little bit under his arm so that it functions somewhat like a cushion . beth harris : although it is a little bit hard for you to imagine him walking up to this rock , laying down the leopard skin , and then somehow lying on it . steven zucker : no , it 's a conceit . beth harris : it is . steven zucker : so you said that this is hellenistic , and it certainly is , in so many ways . but it is clearly informed by the classical tradition that had come before it . beth harris : in terms of its treatment of the human body and its attention to musculature and anatomy . steven zucker : absolutely . and i think that 's really clear in the torso . beth harris : we can see the folds of his flesh in his abdomen , or the careful articulation of the muscles in the shoulders and the armpit . this is an amazing understanding of human anatomy . steven zucker : but it is also a little bit off-kilter . you can see that the ribcage is pushing a little bit to his left . and so the whole thing has a gentle turn to it , making it even more complex . beth harris : there is a turn in the torso , and we see that in other ancient greek sculptures , like the belvedere torso . and although this was found 100 years after michelangelo , or a little bit less , you can see how that kind of twisting and torsion in the body was something that michelangelo would pick up on . steven zucker : i think if michelangelo had ever had the opportunity to see this , he would have absolutely loved it . beth harris : no question .
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and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves .
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0 is there any any indication of what the figures left arm would have been doing ?
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steven zucker : dionysus , the god of wine , did n't like to be lonely . he was surrounded by satyrs and by maenads . he loved to party . beth harris : and you ca n't party alone . steven zucker : no , you ca n't party alone . and of course , those satyrs would become tired sometimes , after they drank a bit too much . and that 's exactly the subject of the barberini faun that we 're looking at . beth harris : now , a satyr is not a human being . he may look human to us , but he 's , in greek mythology , part animal , really . steven zucker : that 's right . he 's a subhuman . the hierarchy of the gods were the gods of mount olympus at the top . then you had heroes that were half divine and half human . then you had humans . and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves . beth harris : yeah , you can see the tail actually coming from behind his left thigh . that 's where i first noticed it . steven zucker : and for the greeks , these particular subhumans , the satyrs , were half civilized and half wild . and so it was a wonderful way to express the uncultivated , the kind of barbaric qualities of human nature . beth harris : his name is the barberini faun . he 's not really a faun . he 's really more a satyr . but he 's called the barberini faun because when he was discovered in rome , near the castel sant'angelo in 1625 , the pope at the time was from the barberini family . and everyone recognized how spectacular this figure was . and the pope said , well , i officially declare this to be part of my family collection . steven zucker : he wanted to do that because it was so important , not only as just a stellar example of sculpture , but we think that this actually dates to the third century bce . and that it is an original greek sculpture . beth harris : although it 's always very hard to tell whether something is a greek original or a later roman copy . steven zucker : it could be a terrific copy . we do know , though , that at least a portion of it has been restored . and you can see those restorations quite clearly in the lower part of the left thigh and almost the entire right leg and foot . beth harris : so this spectacular sculpture ended up here in munich when it was acquired by prince ludwig of bavaria in the early 19th century . quite a sculpture to add to his collection for his new museum . steven zucker : it 's an amazing thing to think that this was likely found in the moat of hadrian 's tomb in what is now castel sant'angelo in rome . i imagine people were vying to purchase this . beth harris : it 's incredibly erotic . this figure has his legs spread . he 's in a drunken , half sleeping , half awake state . steven zucker : we can see that in his body . on the one hand , it 's absolute exhaustion . he is just dead tired . but on the other side , you can see the agitation of his body . there 's tension there . look at that right leg , the way it 's pushed up . now , that part is a restoration . but we know that that 's pretty much the placement because of the rock on which it sat . beth harris : and you can see from his face , too , that there 's a combination of exhaustion and restlessness . steven zucker : well , look at that face . it is just spectacularly sensitive . and i love the fact that it 's not symmetrical . his head is pushed over to the side . and if you look at his cheek straight on , you can see that gravity is compressing the right side of his face and it 's expanding the left side . and so there really is this intense naturalism , this observation of the elastic qualities of the human body . beth harris : now , we 're in the hellenistic period , where ancient greek artists are expanding their subject matter . so we do n't just have the heroic , ideal , athletic nudes that we saw in the classical period . but here , the art is exploring more emotional states , more varieties of subject matter . steven zucker : that 's right . sometimes this is even referred to as the hellenistic baroque , because of its willingness to remove the reserve that we associate with the high classical period before . beth harris : he 's certainly not reserved in any way . steven zucker : no , not at all . so what are the other accoutrements ? what are the other symbols that identify him as a satyr ? as if the tail and the ears and the wanton abandon quality was n't enough , you can see that he 's laid out a leopard skin . he 's on a rock , and it 's certainly protecting him from the roughness of the rock . and you can see that he 's even keeping his heel on it . it 's softer , and he 's rolled it up a little bit under his arm so that it functions somewhat like a cushion . beth harris : although it is a little bit hard for you to imagine him walking up to this rock , laying down the leopard skin , and then somehow lying on it . steven zucker : no , it 's a conceit . beth harris : it is . steven zucker : so you said that this is hellenistic , and it certainly is , in so many ways . but it is clearly informed by the classical tradition that had come before it . beth harris : in terms of its treatment of the human body and its attention to musculature and anatomy . steven zucker : absolutely . and i think that 's really clear in the torso . beth harris : we can see the folds of his flesh in his abdomen , or the careful articulation of the muscles in the shoulders and the armpit . this is an amazing understanding of human anatomy . steven zucker : but it is also a little bit off-kilter . you can see that the ribcage is pushing a little bit to his left . and so the whole thing has a gentle turn to it , making it even more complex . beth harris : there is a turn in the torso , and we see that in other ancient greek sculptures , like the belvedere torso . and although this was found 100 years after michelangelo , or a little bit less , you can see how that kind of twisting and torsion in the body was something that michelangelo would pick up on . steven zucker : i think if michelangelo had ever had the opportunity to see this , he would have absolutely loved it . beth harris : no question .
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and then you had subhumans , and even below that , monsters . a satyr would be a subhuman . and if you look really closely , you can tell that , although he looks quite human in most ways , he 's got a tail , pointy ears , and sometimes this is even represented with hooves .
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if it is a true greek piece would it have been painted originally ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction .
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in your last example , why was the second person pushing not also pushing against friction but only pushing against the force of the first guy ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction .
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would there not be friction no matter what direction you push the rock on the ground ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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how do you calculate unbalanced force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up .
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in the 4th diagram , what if the air resistance is 5n in total ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards .
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then will the rock be in uniform motion , or just stay still in the air ( sounds weird though ) ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up .
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what is terminal velocity and what does it or what does in not have to do with air resistance ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation .
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so the scenarios 3 , 4 and 5 have net force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward .
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if the rock 's wieght is being cancelled out by gravity , why over many many years does it eventually sink into the ground , does the gravity = 5 newtons and the upward force equal 4.9999999 ... n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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if one applies 1 newton force on an object to move , then what will be the frictional force acting on it ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards .
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why is n't there 2 newtons of friction acting in the leftward direction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards .
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what exactly causes the normal force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground .
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if i exert pressure on a table how does the table exert pressure on me ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out .
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so this is probably a really dumb question , but why does n't air exert as much of a normal force as the ground ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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does each atom have a set amount of force it can apply to an object , and since there are more atoms in the ground than in the air the air does n't have as powerful of a normal force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards .
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would it mean that the rock would be floating in the air ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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also if the air resistance is greater than the force of the rock falling down , would the rock be floating upward ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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why do you say that the force of attraction is 5n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left .
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can someone explain to me how to apply in an equation of f ( net ) = m*a ( net ) what to do ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario .
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what if there is another of force of friction acting for the orange guy in scenario # 5 ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ?
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sal says that because of the second guy 's motion to the left along with the friction , the total force to the left is 3n while the first guy is applying a force of 4n should n't the second guy also be experiencing a frictional force of 2n as the first guy ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock .
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in the 5 th example , if the guy on the left is applying 4 n of force on the rock , then the rock is also applying 4 n of force but in the opposite direction ( newton 's iii law ) , then how come the guy is applying 4 n to the right and the rock is exerting only 2 n of force in the opposite direction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards .
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why ca n't internal forces influence the motion of an object ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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quick question , if we know the friction force on the rock is going to be 2n and we push with 1 n , why does n't the rock move backwards ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction .
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in scenario 3 with the rock shouldnt air resistance push against the motion as well ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up .
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the rock is huge so should n't it push air particles on the way and experience air resistance when the guy is pushing it ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing .
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on the third diagram , why is friction only exerting 2newtons ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction .
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i thought by the newton 's third law of motion , to every action there is always an equal and opposite reaction , so should friction be exerting a force of 3 newtons since the guy is exerting 3 newtons in the opposite direction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth .
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4 , can you explain to me why exactly the force applied by the orange guy does not experience the force of friction in the opposite direction , while on the other hand , the pink guy experiences both the orange guy 's force and the force of friction in the opposite direction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here .
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so the lower the net force , the slower the rock will accelerate ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity .
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but in the third scenario when the rock was on the ground and the guy was pushing the rock , why is it that when the guy was applying 3n of force , there was only 2n of force acting opposite to it ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction .
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0 , if the purple guy were to push with a force of 1n , would the force of friction still be 2n or 1n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left .
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wo n't the orange character have friction pushing back on his applied force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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if the force of friction is 5n and the pushing force is 3n to the right would the rock move to the left because 5n ( friction ) > 3n ( force from person ) ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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how do you calculate net force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation .
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how exactly does the ground press up on everything ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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where does the force applied by the person in the second diagram go ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green .
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after the rock would have fallen when it hit the ground why does it stop moving assuming that because of newtons first law of motion that it has to be opposed by an unbalanced force , so how is the ground unbalanced if it only pushes upward with normal force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so is n't an unbalanced force a violation of newton 3rd law ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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how does newton 's third law work with unbalanced forces ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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and can you please give almost alike situations ( any situations ) which can differ third law and unbalanced force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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how can the friction be lesser than the force applied ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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should n't friction offered be equivalent to the magnitude of the force applied ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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what exactly is the net force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity .
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a balloon is flying in sky freely what is the force acting on it ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards .
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what is a scenario where the normal force is greater than gravity ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction .
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if i have pushed a rock with 1n and it has already friction of 2n what is going to be the case ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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should n't force of friction be 3n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing .
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in the last example , two guys were pushing the boulder against each other , so why is there only friction force to the left and no friction force to the right ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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friction only acts when an object rubs against the ground i.e it is in motion right ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green .
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so i understand normal force but is electrostatic or gravity contact force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards .
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one more question : is the presence of matter force ( apart from gravity ) ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards .
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there 's a thing i 'm a little confused about : the force of gravity is included on the weight , right ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up .
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this has nothing to do with the topic , but is air resistance affected by wind at the time ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right .
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when sal says the guy was pushing a rock with 3 n , should n't the friction also be 3 n ( instead of 2 n ) because for every action , there is an equal and opposite reaction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards .
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is there a maximum amount of normal force the earth can support ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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i might sound a little stupid but why was the force of friction less than the pushing force in the 3rd scenario , third law states that every action has an equal and opposite reaction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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so when sal is talking about air resistance , am i correct in understanding that it is a force of friction but not the normal force upon the rock by the air ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground .
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how can i get the intuitive understanding of a newton ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction .
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so a newton is a vector ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ?
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the guy resisting the first guy will also experience a fore of friction or am i insane at physics ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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could somebody explain to me what we exactly mean when we say that friction is a self-adjusting force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out .
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is it possible that the normal force of the ground is higher than the weight of the rock ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing .
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since the orange guy is only putting one newton of force then would n't friction stop him form moving the rock because 2n ( friction ) > 1n ( force from person ) ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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for the fourth scenario , the one with two guys pushing , should n't the force the red guy on the right is applying on the rock have an opposing force of friction too ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ?
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i know friction is a reactionary force that tries to prevent or stop motion , and since the guy on the right is pushing to the left , should n't friction try to counter his force too just like it does with the purple guy on the left ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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if all forces have an equal reaction force in the opposite direction from newtons third law , how can there be a net force at all ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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in the fifth case , wont the orange guy who is opposing the force experience friction in the opposite direction to him and since 1n is less than the frictional force ( here , 2n ) , how come the pink guy experiences 3n of force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing .
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in the fifth picture , why does n't the force of friction also effect the orange man ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 .
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in the third diagram , why would the friction be 2n why would it not equal to the amount of force generated by the guy ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction .
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in general how do normal forces and their calculation vary in a 3 dimensional plane ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ?
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in the last diagram , if the purple guy faces force of friction then why doesnt the peach guy face it ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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is the amount of friction always equal to the amount of force applied on an object ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right .
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on the fifth rock where there are two people pushing it , would n't the small peach guy be pushing against the 2n of friction ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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during any of the diagrams where the rock is being moved sideways , why is n't air resistance taking effect there , i understanding its facing friction but wo n't there still be air resistance ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out .
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sal draws another man opposing the pink man 's force .why wont the other man experience friction of the ground ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards .
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for the fifth example , around 0 , would n't the friction affect the orange guy ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction .
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so : are collinear forces concurrent ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing .
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what if the friction was greater than the force ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards .
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why is the opposing force still 2n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out .
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could n't air resistance also be interpreted as the normal force the air is applying to the rock ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios .
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in the last scenario , when the little guy exerts a force of 1n to the left , shouldnt a force of friction act on the right of 1n and hence the total force acting on right should be 5n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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in sal 's example about the force of 3 n to the right resisted by a force of 2 n friction , what happens when the force ceases ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right .
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how can i think about the resistance that continues after the initial push of 3 n ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up .
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when there is a car in motion , if there is a balanced acceleration and air resistance , will the car come to stop ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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does having a net force mean the object is accelerating or just moving ?
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you 'll hear the terms , balanced forces and unbalanced forces a lot when you 're dealing with physics and what i wan na do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced . so let 's start with the scenario where we have the ground . and then sitting on the ground we have a rock . now the force of gravity is going to be pulling the rock downwards towards the center of the earth and it 's going to be pulling it , as essentially the weight of the rock , it 's going to be pulling it downwards , let 's say with a force of 5 n downwards . but then the rock is being supported by the ground , the ground is keeping it from being plummeted downward . so the ground is providing an upwards force or normal force in this situation . the ground is providing a normal force , i 'll do it in green . the ground is providing a normal force in this situation . so these forces have the same magnitudes but they 're going in opposite directions . so that is the first scenario . now let 's think about another scenario . so i 'll draw the rock again . we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards . and there 's still a normal force , the ground supporting the rock of 5 n upwards . 5 n upwards . and now there 's some character who 's trying to push the rock . so we have some character here and he 's trying to push the rock and he 's applying a force of 2 n to the right . but then there 's a force of friction between the rock and the ground that is going 2 ... i 'll do friction in orange 2 n to the left so that right over there is the force of friction . it 's going against that guy 's pushing . now let 's do another scenario . once again a very similar scenario . let 's draw another scenario where i have a rock now . maybe the same rock . and here i have a 5 n force downwards . force of gravity , like the rest of the scenarios . and i have the normal force . the rock is being supported by the ground 5 n upwards . and this guy over here has been able to push a little bit harder . he 's pushing a little bit harder . he really put his back into it . and now he 's pushing with a force of 3 n to the right and the force of friction is still 2 n to the left . so that right over there is the force of friction . now let 's do a couple of more scenarios . now let 's imagine that this is the ground . and i have the rock . the rock is not resting on the ground . so the only force i have acting on the rock right now is the force of gravity , acting downward . we 're assuming we 're not going to think too much about -- actually let 's think about it a little bit , let 's also put , so let 's put it ... so i have the force of gravity . that 's 5 n down . but i have some air resistance here . you can view it as the force of friction of the air , and let 's say that is 1 n up . this is the force of friction or you can call it air resistance . as if this thing bumps into all of the air particles as it is falling to the ground . the last scenario i 'll draw with the rock again as that seems to be the theme of the video . the last scenario , that 's the ground . the rock is resting on the ground . the rock is resting on the ground . so i have the force of gravity , 5 n downwards . the rock is being supported by the ground , 5 n upwards . and now this guy is pushing really hard . so now he 's applying 4 n in that direction . you have 2 n from the force of friction , i wo n't that draw just yet ; and you also have another character right over here , who is trying to keep this guy from pushing the rock . so he 's pushing in the other direction at 1 n. so you have 2 n of the force of friction . you have this guy pushing 1 n against this guy 's motion to the left , so between this guy and the force of friction , you have 3 n going left . so now i 'll let you think about which of these have an unbalanced force in them , or another way to think about it , which of these have a net force going on ? so let 's look at the first scenario , we have a 5 n force of gravity acting towards the centre of the earth . 5 n normal force of the ground supporting the rock . these have the same magnitude in the exact opposite directions so they cancel out . these forces completely balance each other out . there is zero net force going on , there are no forces the way i 've drawn it , going on in the horizontal direction . so you have zero net force , these right here are balanced . we would not consider this one of the scenarios we see an unbalanced force . let 's go to scenario 2 . once again , 5 n up and 5 n down , they are balancing each other . then in the horizontal direction , this guy is pushing of 2 n to the right is being completely balanced by the force of friction of 2 n to the left . because they 're balanced there is no net force and this rock is n't going to accelerate . so once again these are all balanced forces or there 's no net force going on right over here . in scenario 3 . once again , in the vertical direction . the force of gravity is being balanced by the normal force of the ground . keeping the rock from plummeting or accelerating towards the centre of the earth . and you do have two forces that are counteracting on the horizontal direction . this guy 's pushing harder with 3 n , but the force of friction is now 2 n to the left . so you do have a net force to the right . 3 n to the right , 2 n to the left . you have a net force of 1 n to the right . or you see it 's right based on how i drew the vector . so you do have a net force or in another way of thinking about it , that this is a scenario where you have unbalanced forces , in particular , in the right left direction . now let 's look at scenario 4 . we only have forces acting in this vertical direction . you have the force of gravity 5 n downwards . you have a counteracting force , the force of air resistance , i n upward . but they do n't completely balance out . there is still a net force of 4 n downwards . therefore this is an unbalanced situation . and finally in the last scenario . we 're sitting on the ground in the vertical direction , normal force counteracting the force of gravity . those are balanced . but in the horizontal direction . to the right we have more force , 4 n , than what we have going to the left . 3 n is the guy on the right plus the force of friction . so in this situation there is a net force in the rightward direction . a 1 n force to the right or 1 n net force . this is a scenario where we have unbalanced forces .
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we 'll assume it 's the same rock . the force of gravity is still downwards . 5 n downwards .
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a balanced force can still be moving , but just not accelerating , correct ?
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