source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3801 | inorganic-chemistry, home-experiment
Title: Make a silver zinc battery I have a shaver that runs off a rechargeable battery that is dying. Would it be feasible to make a silver zinc battery and use it to replace the existing battery? Cost is not an object, anything less than $2500 I would consider doable. I have a machine shop and a small chemistry laboratory with the standard equipment and glassware, including high vacuum capability, a centrifuge and simple glass blowing capability.
I found a book on silver-oxide zinc chemistry and battery design, but it is $500 and I don't want to spend that if the information can be obtained just as easily elsewhere.
I have tried to find commercial options, but had no luck. Most silver zinc batteries seem to be just for large (multi-million dollar) military or satellite applications. Sony makes a line of silver oxide primary cells for hearing aids, but these are not rechargeable. There is a company called Ultralife that makes medical and military batteries and might have something viable, but before I call them I wanted to check out the opinion of the experts here. This turns out to be very difficult to do for two reasons. One problem is that the voltage of a silver cell is different from that of Ni-Cd cell, so it would require a specialized, multi-cell configuration to emulate the voltage characteristics of the Ni-Cd rechargeables.
The other problem is that silver cells generally have a sophisticated frame inside of them that is produced by an intricate high-temperature welding process. To duplicate this process and produce a suitable frame would require a significant amount of experimentation and work.
The following is multiple choice question (with options) to answer.
Flashlights require batteries | [
"to properly illuminate objects",
"to illuminate alien creatures",
"to be used as a weapon",
"to meet height values"
] | A | a flashlight emits light |
OpenBookQA | OpenBookQA-3802 | c++, game
if (m_XSpeed > 0)
{
double speed = m_XSpeed + (-AirResistance()) * m_XMotionTimer.totalTime();
if (speed > 0)
{
((Actor*)GetOwner())->Move(utility::Vector2((int)std::round(speed), 0));
}
else
{
m_XSpeed = 0;
m_XMotionTimer.stop();
m_XMotionTimer.reset();
}
}
if (m_XSpeed < 0)
{
double speed = m_XSpeed + AirResistance() * m_XMotionTimer.totalTime();
if (speed < 0)
{
((Actor*)GetOwner())->Move(utility::Vector2((int)std::round(speed), 0));
}
else
{
m_XSpeed = 0;
m_XMotionTimer.stop();
m_XMotionTimer.reset();
}
}
if (m_YSpeed > 0)
{
double speed = m_YSpeed + (-AirResistance()) * m_YMotionTimer.totalTime();
if (speed > 0)
{
((Actor*)GetOwner())->Move(utility::Vector2(0, (int)std::round(speed)));
}
else
{
m_YSpeed = 0;
m_YMotionTimer.stop();
m_YMotionTimer.reset();
}
}
if (m_YSpeed < 0)
{
double speed = m_YSpeed + AirResistance() * m_YMotionTimer.totalTime();
if (speed < 0)
{
((Actor*)GetOwner())->Move(utility::Vector2(0, (int)std::round(speed)));
}
else
{
m_YSpeed = 0;
m_YMotionTimer.stop();
m_YMotionTimer.reset();
}
}
}
The following is multiple choice question (with options) to answer.
If I wanted to make something move faster I could | [
"slow it down",
"stomp on it",
"stop it",
"roll it"
] | D | as force exerted on an object increases , distance travelled will increase |
OpenBookQA | OpenBookQA-3803 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Some plants have developed the ability to do what with their seeds? | [
"put makeup on",
"go running",
"catapult",
"do magic"
] | C | seed dispersal has a positive impact on a plant |
OpenBookQA | OpenBookQA-3804 | newtonian-mechanics, classical-mechanics, biophysics
Title: Walking & Swinging How can I show that the most convenient way to move the arms while walking is swinging them back and forth, alternatively?
To pose the question in another way: can I prove, starting from the conservation of momentum and angular momentum, that given a rigid solid body moving at constant speed and with two appendices on the side, this appendices will move as our arms do when we walk "freely"? This is a responce to usumdelphini's comment:
Is there a way to show this formally, without relying on experimental data?
I'm not going to attempt a deep analysis of walking, but it's fairly straightforward to show that using your arm reduces twisting. Suppose you're looking down on the person walking from above, and suppose they're a cylinder $^1$. Then you'd see something like:
When you move your right leg forward this takes some force $F$, and by Newton's third law there is an equal and opposite force on the point where the leg is attached to your body (the green dot). This causes a torque on your body of:
$$ T = Fr $$
and as a result your body will tend to twist clockwise.
Now suppose you move your left arm forward at the same time:
Moving your arm creates a torque of $T_{arm} = fr$ in the same way, but the torque is in the opposite direction. So the net torque on your body is:
$$ T = Fr - fr = (F - f)r $$
and the result is that your body will twist less.
$^1$ traditionally we assume everything is spherical, but I'll make an exception in this case
The following is multiple choice question (with options) to answer.
Which of these allows humans to walk around? | [
"luck",
"glucose",
"magic",
"sand"
] | B | an organism breaks down sugar to release energy |
OpenBookQA | OpenBookQA-3805 | species-identification, marine-biology
Title: help identify this fish
I came across this washed up fish in Panama City, Florida in November 2015. I'm guessing it's a puffer fish but I can't find anything like it online.
Thanks. This is a kind of trunkfish. (They have different names, this could be a smooth or spotted trunkfish.). It's really a lovely and comical little fish when observed alive in coral reefs. It has the ability to change its coloration depending on whether it's excited or calm, or to minimize its contrast to the background. It is related to puffer fish.
It has a boxy, triangular body shape, and propels itself with relatively tiny, delicate fins. Like pufferfish, they are toxin producers.
In death, the body shape and coloration are different, of course. Never saw a dead one before; sad. The juveniles are adorable:
Members of this family occur in a variety of different colors, and are notable for the hexagonal or "honeycomb" patterns on their skin. - Wikipedia
The following is multiple choice question (with options) to answer.
What is most like a fish? | [
"offspring of frogs",
"a desk",
"a diva",
"a solar system"
] | A | young amphibians breathe through gills |
OpenBookQA | OpenBookQA-3806 | genetics
Title: What distinguishes Mendelian Inheritance from Non-Mendelian Inheritance? I'm having some trouble determining what exactly is the difference between Mendelian inheritance and non-Mendelian inheritance. For instance, I understand that chromosomal abnormalities such as Down's Syndrome fall under non-Mendelian inheritance because they concern chromosomes, not single genes. And I also understand that Mendelian inheritance concerns single genes, as in Sickle-cell anemia (which is an autosomal recessive disorder).
What confuses me is the fact that our textbook discusses dihybrid and trihybrid (concerning 2 genes and 3 genes, respectively) crosses under the Mendelian inheritance chapter, when to me it seems like these crosses are non-Mendelian because they deal with multiple genes. However, Gregor Mendel did in fact use the dihybrid cross to deduce the law of independent assortment, so I'm completely confused. Could someone please clarify this for me? I'm afraid that I'm maybe misinterpreting something. You can discuss multiple genes within the framework of Mendelian inheritance; what you're probably thinking of, though, is the fact that Mendelian inheritance doesn't recognize the idea of multiple genes that contribute to a single trait.
For example, if there is a gene that controls petal color (blue vs. white, with blue = dominant) and a gene that controls height (short vs. tall, with tall = dominant), then Mendelian inheritance predicts that two short plants with white flowers will only produce short plants with white flowers.
But if there are multiple genes that interact to determine height in a complex way, that's outside the scope of Mendelian inheritance.
The following is multiple choice question (with options) to answer.
Which relationship involves inheritance of genetics? | [
"mother-daughter",
"friend-friend",
"teacher-student",
"husband-wife"
] | A | inheriting is when a inherited characteristic is passed from parent to offspring by genetics |
OpenBookQA | OpenBookQA-3807 | magnetic-fields, ferromagnetism
Title: Technical Term for Material That is Only Magnetic Next to A Magnet I was wondering what the technical term is for some metal(like a refrigerator door) that is not magnetic on its own like neodymium but when there is a magnet in its vicinity, it attracts to the magnet. Neodymium has a polarity but these metals don't have one, they just stick to a magnet. Is it called ferromagnetism? As far as I know there is no single term to refer to a material that is attracted by magnetism but not a magnet. Rather, there are terms that describe a material's magnetic behaviour regardless of its magnetized state.
There are a few versions. Ferromagnetic, paramagnetic, and diamagnetic.
Ferromagnetic is like iron it will be attracted to other magnets, but can also be magnetized and turned into a permanent magnet.
Paramagnetic and diamagnetic materials can't be turned into permanent magnets. The difference might be considered nitty gritty and I'm not qualified to comment.
But it sounds like you're asking for a specific term for a material that is ferromagnetic, but not currently magnetized. I don't know of one.
The following is multiple choice question (with options) to answer.
Which is likeliest to attract a magnet? | [
"feathers",
"a wrench",
"hair",
"blood"
] | B | if a magnet is attracted to a metal then that magnet will stick to that metal |
OpenBookQA | OpenBookQA-3808 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
Seals have an instinct to give birth in the same area every year. Where do seals give birth normally? | [
"Jupiter",
"space",
"waterfronts",
"houses"
] | C | seals every year return to the same beaches to give birth |
OpenBookQA | OpenBookQA-3809 | energy, visible-light, solar-cells
Title: Why are solar panels blue, rather than black, when black absorbs more light? This is an image of a solar panel array, courtesy of Wikipedia.
Some of these look rather black, but most of them are blue.
As far as I know, solar panels work by absorbing "light energy", and then converting this to "electrical energy". Some of the energy is also converted into "heat energy", as is natural; things put into sunlight will warm up. Lastly, some of the "light energy" will get reflected as "light energy". But only on specific wavelengths. That's how we can see colors...
Now, black objects reflect less light than blue objects. So, given a certain amount of light denoted by $x$, it should hold true that blue.reflected(x) > black.reflected(x). Inversed, it should hold that (black.heat(x) + black.electrical(x)) > (blue.heat(x) + blue.electrical(x)). Basically, because there's less light reflected, more energy is absorbed.
So if a black object (say, a black solar panel) absorbs more energy than a blue object (like a blue solar panel), why are blue solar panels still in use? Why aren't solar panels black, as to absorb the maximum amount of energy from the light? The colour you're seeing is from the very small fraction of light that the panels are reflecting. The vast majority of light is being absorbed to generate electricity.
Why some of the panels appear slightly blue while others don't I don't know. Presumably there must be small differences in the manufacturing process. The absorptance of solar panels does fall off at the extreme blue end of the spectrum, so you would expect the reflected light to have a blue tinge. A quick Google found this article that includes a typical absorption spectrum:
The following is multiple choice question (with options) to answer.
Which absorbs more sunlight? | [
"palm frond",
"a mirror",
"maple syrup",
"Wednesday"
] | A | as flatness of a leaf increases , the amount of sunlight that leaf can absorb will increase |
OpenBookQA | OpenBookQA-3810 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
sharp beaks are a kind of adaptation for catching | [
"sticks",
"small food beings",
"bubbles",
"rocks"
] | B | sharp beaks are a kind of adaptation for catching prey |
OpenBookQA | OpenBookQA-3811 | 5. Originally Posted by Nath
"I have 2 children. One is female. What is the probability the other is also female?"
This puzzle appeared in New Scientist magazine, and a similar one in Scientific American several months back. The consensus among mathematicians (according to the articles in the magazines), including a friend of mine (who has PhD in Maths from Cambridge), is that the answer is 1/3.
I've seen several statements which claim to "mathematically prove" the answer to the question is 1/3, but I'm still not convinced. I think it's 1/2.
I'm interested to get some more opinions...
Here is an alternative "logical" way to consider this.
There are 4 possibilities in regard to the children being boy or girl.
The probability of having a boy and a girl is twice the probability of having 2 girls,
and is also twice the probability of having 2 boys.
(i) 1st and 2nd children are girls
(ii) 1st child is a girl and the 2nd is a boy
(iii) 1st child is a boy and the 2nd is a girl
(iv) 1st and 2nd children are boys
GG
GB
BG
BB
One is female.
This reduces to...
GG
GB
BG
3 cases of equal probability and in only 1 of these cases is the other child also a girl.
Hence the probability of the 2nd child also being a girl is 1/3.
Also note that in 2 of these 3 cases, the 2nd child is a boy,
therefore, if one of the children is a girl, the probability that the other is a boy is 2/3.
6. ## Solutions
This was my solution, but alas my friend disagrees:
I have 2 children, 1 is female. This gives four possible scenarios:
1. The female has a younger sister
2. The female has an older sister
3. The female has a younger brother
4. The female has an older brother
Each of these events has a 25% probability, so the probablity the female has a sister = 25% + 25% = 50%.
---
My friend, with the PhD in Maths thinks the following:
The following is multiple choice question (with options) to answer.
two females are incapable of | [
"conjuring kin",
"talk",
"dance",
"jog together"
] | A | two females can not usually reproduce with each other |
OpenBookQA | OpenBookQA-3812 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
Sticky balls from a plant can grow a new plant miles from the original because | [
"a bear unknowingly transported it",
"they bounced when they fell",
"they were transported by ants",
"they were carried there by a pterosaur"
] | A | if seeds stick to the fur of an animal then that seed will be transported by the animal |
OpenBookQA | OpenBookQA-3813 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
Herbivores who live in climates that get cold must find other sources of food in the winter because plants | [
"fly",
"cry",
"Eat candy canes",
"will be gone"
] | D | if an animal relies on plants for food then that animal must store enough food to last through the winter |
OpenBookQA | OpenBookQA-3814 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
Rabbits with white fur are hardest to detect in | [
"a forest in Spring",
"The middle of a well-lit street",
"Mexico in the Winter",
"the arctic in Winter"
] | D | snow falls during the winter in the arctic environment |
OpenBookQA | OpenBookQA-3815 | meteorology, mesoscale-meteorology
In a sense, the fact pressure at one elevation induces changes\motion in another elevation maybe shouldn't seem any less weird than the fact that a low-level low pressure system can affect the wind and weather hundreds of miles away from it horizontally. This isn't spooky action at a distance, this is a continuous fluid where changes to one part of it causes impacts on another part.
The following is multiple choice question (with options) to answer.
How is a place of lower elevation affected by flooding when compared to a higher location? | [
"It is more resistant than a higher place",
"The lower area is already flooded",
"It is more affected by the flood",
"It is impossible to flood a lower elevation location"
] | C | as elevation of a place decreases , how much a flood will affect that place will increases |
OpenBookQA | OpenBookQA-3816 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
Which are likeliest to rely on nonrenewable resources? | [
"windmills",
"dams",
"solar panels",
"cell phones"
] | D | aluminum is a nonrenewable resource |
OpenBookQA | OpenBookQA-3817 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Cows only eat what? | [
"flora",
"animals",
"water",
"bugs"
] | A | cows only eat plants |
OpenBookQA | OpenBookQA-3818 | electric-circuits, electric-current, electrical-resistance, batteries, short-circuits
Title: The importance and the role of a switch in an electrical circuit There is this simple test:
Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed:
a] The brightness of $A$ and $B$ remains the same, while $C$ goes out.
b] The brightness of $A$ and $B$ remains the same, while that of $C$ is halved.
c] The brightness of $A$ and $B$ decreases while $C$ goes off.
d] The brightness of $A$ and $B$ increases while $C$ goes off.
For my opinion the answer to this question is D because the switch (which has a resistance of $0\, \Omega$ has a node connected before the third bulb C) that "interrupts" the circuit. But, going into detail, according to Kirchhoff's first law the current should also go on the third bulb as in the first red node it divides into two currents $I_1$ and $I_2$. The current $I_1$ goes for example in the key $S$ and $I_2$ in the third bulb. The key and the third bulb have the same potential difference. I believe that the current $I_2$ passes through the third bulb but the current passing through it is so small that it does not turn on.
I made a point. When an individual is operated on at the heart and puts a by-pass (a bridge), blood will flow on the tube that detects the by-pass and the occluded artery (the third bulb) where blood will flow slowly, over time it will atrophy.
If the circuit were like the one drawn in the picture I would answer the b).
My question is: I have not very clear the rule of a switch in a eletric-circuit.
In fact, I find it difficult to give an answer to the following image.
The following is multiple choice question (with options) to answer.
One type of electrical circuit that requires a switch could be | [
"running",
"diving",
"dimming table lights",
"swimming"
] | C | when a switch in a simple series circuit is closed , electricity will flow through the circuit |
OpenBookQA | OpenBookQA-3819 | 4. Jun 1, 2004
### Physics is Phun
I am afraid I am confused and I may have confused you with my question. So I have a cylinder and a piece of string. If I just wrap the string around the can the length of the string will be the circumference. I want to find the length of the string when it is spiraled around the cylinder from one end to the other. Picture a barber shop pole or the stripes on a candy cane.
I have tried doing this with a tin can and fishing line. The fishing line has basically no thickness so I am not worried with that. The circumference of the can I measured 32.5cm, the length 16.5cm. When I wrap the fishing line around the can once (like a barber shop pole) I measure 36cm, when I wrap it twice I get 66cm. Now this does match with the equation L = 2pi *Y*X where y is the radius and x is the length. The length of the string is 3cm longer when wraped around the cylinder end to end than just the circumference I can't see is any relation to the length.
5. Jun 1, 2004
### jcsd
Well the surface of a Cylinder is Euclidan, so imagine drawing the line your string makes and unwrapping the surface of the cyclinder, what would it look like?
If you wnat the string to go from top to bottom (or bottom to top) and once around the cylinder it's lenght will be given by Pytahgoras's theorum where r is the radius and h the height:
$$L^2 = 4\pi^2r^2 + h^2$$
For n twists it will be:
$$L^2 = n^24\pi^2r^2 + {h^2}$$
Last edited: Jun 1, 2004
6. Jun 1, 2004
### robphy
Imagine a label on the can. If you unroll it, it's a rectangle with the same height of the can and the width of one circumference. The string wrapped once like a barber-pole on the can would be the diagonal of that rectangle.
sqrt(32.5^2+16.5^2)=36.44
The following is multiple choice question (with options) to answer.
To measure the length of a elephant's trunk you would need | [
"a tape measure",
"a tusk",
"a scale",
"a pool"
] | A | a meter stick is used to measure length |
OpenBookQA | OpenBookQA-3820 | materials, chemical-engineering, plastic, safety
Title: Why do glass windows still exist? (Why haven't they been replaced by plastics?) Glass is fragile and impractical to transport, install and repair. Even worse, glass kills and hurts people when it breaks. Falling to the streets like guillotines during earthquakes and bomb raids. During wars people put tape on their windows to prevent shattering. When that meteor exploded over Chelyabinsk, people got hurt by standing inside of a window watching the sky when the shock wave hit them.
There are perfectly transparent plastics, for example the PET material used to make coca cola bottles. Why aren't windows made out of that instead of glass (fragile ceramics)? It seems to be much cheaper, safer and more practical to handle. Is there any advantage at all to make windows out of glass? Is this a billion dollar business idea, and if so, why haven't anyone realized it yet? There are two main reasons why glass is still preferred over say PMMA.
The first is durability. As long as it isn't broken, the glass in a window can easily last for hundreds of years in good condition. In particular it is a lot more resistant to scratches than comparable plastics and isn't really subject to much in the way of environmental degradation. Windows are very prone to getting scratched when they are washed as they accumulate small particles of grit on their surface which gets rubbed around the surface during cleaning. Even with scratch resistant coatings no transparent plastics get anywhere near the hardness of glass.
Most glasses are also much more resistant to environmental degradation from sunlight and various chemicals in the environment. Even the most resistant plastics start to discolour and become brittle over time.
The second factor is stiffness. Glass has a much higher Young's Modulus than PMMA. In bottles etc which are stiffened by their shape this doesn't matter much but, as windows tend to be large, flat, thin panels stiffness is a big issue, affecting their ability to be sealed into their frames and their optical properties. So a plastic window would need to be substantially thicker than a glass one to have the same stiffness with consequences for optical quality and cost.
There may also be issues with gas permeability in the context of double glazed windows.
The following is multiple choice question (with options) to answer.
What scratches glass easily? | [
"a rubber pencil eraser",
"a crystal that regulates electronic oscillators in watches",
"a soft linen towel",
"a round piece of ice"
] | B | quartz scratches glass easily |
OpenBookQA | OpenBookQA-3821 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
It's quite common for birds feeding on seeds from flowering trees in some tropical waters to get weighed down, pricked and even entangled in the branches because | [
"seeds sprout better on the ground",
"smooth seeds need water to reach other islands",
"the seeds have a thick, sticky coating with hooks",
"scavengers also hunt for seeds with mucousy coatings"
] | C | birds are a vehicle for spreading the seeds of a plant |
OpenBookQA | OpenBookQA-3822 | gravity, general-relativity, dark-matter
More detail on the dark matter distribution
Since two-body interactions are negligible, dark matter systems do not thermalize, so their structures are tightly connected to the initial conditions. For example, material accreted earlier settles into lower orbits while material accreted later settles into higher orbits, which implies that the radial distribution of material of a halo is tightly connected to its assembly history. Let $M_\mathrm{acc}(\rho)$ be the mass accreted by the halo when the density of the universe was larger than $\rho$, keeping in mind that the density of the universe drops over time. Also, let $M_\mathrm{halo}(\rho)$ be the halo mass inside radii for which the average enclosed density exceeds $\rho$. Ludlow et al (2013) noted that
$$M_\mathrm{halo}(800\rho)\simeq M_\mathrm{acc}(\rho),$$
that is, material accreted when the universe was denser than $\rho$ settles into regions denser than $\sim 800\rho$.
Despite this, the structures of dark matter halos tend to be pretty consistent.
The mass distribution is pretty close to spherical.
At each position, the distribution of particle velocities is pretty close to isotropic, although this becomes less true toward the edge of the system (where radial or tangential velocities might be favored, depending on the halo's current accretion rate).
As a function of radius, the mass distribution is reasonably well approximated by the NFW density profile. The density of a halo diverges toward the center of the system, although it's expected to converge to a finite value at radii smaller than what is resolved in simulations. It decreases at larger radii.
The gravitationally orbiting system ends at roughly the virial radius, where the enclosed density is $\sim 200$ times the average density of the universe. Outside this radius lie still accreting particles that have not completed full orbits yet.
The following is multiple choice question (with options) to answer.
Which object would have more tightly packed matter | [
"gold",
"gas",
"wood",
"water"
] | A | an organism is a source of organic matter |
OpenBookQA | OpenBookQA-3823 | lidar, laser
Also for reference sunlight hitting the ground delivers over 1kW of light energy per square meter. Which would take over 100000 LIDARS pointing at the same square meter of space to produce the same effect. However most LIDAR sensors point outward and scan all around which means that the power is distributed around. Which means that at say 5m distance, only 3% go into a specific meter radius. And as such you're now looking at needing on the order of 3 million sensors around you at 5 meters away. Back calculating that to a 5 meter sphere you would need over 10000 sensors per square meter of that sphere, which is by multiple orders of magnitude higher than you could physically achieve.
And that's only to produce the level of light that the sun provides, which is a level of light that I am quite happy to walk around in.
As such I don't worry about any health effects of the many LIDARs that might be used in public spaces.
The following is multiple choice question (with options) to answer.
The largest amount of natural illumination will likely occur for a Floridian in | [
"space",
"june",
"october",
"january"
] | B | the amount of daylight is greatest on the summer solstice |
OpenBookQA | OpenBookQA-3824 | the-sun, space, stellar-atmospheres
However, when you have something the Sun or even fog, the optical depth varies with the distance you're looking into that object. I'll talk about fog since it's familiar, but the same idea applies to the Sun's atmosphere. Say you're standing in a forrest and its very foggy out. There's a tree 1 meter away from you that you can see. You could measure your optical depth, $\tau$, of the fog between you and tree and might find that $\tau = 0.15$. Since $\tau$ is less than one, that implies you can see the tree, but the value of $\tau$ also implies how well you can see it. If $\tau = 0$, there's nothing between you and the tree to impede your ability to see it. Let's say there's another tree that's 5 meters away. Now there's more fog between you and the tree and while you can still see it, it is harder to see it. The optical depth of the fog between you and the tree 5 meters away might be $\tau = 0.75$. It's still less than one, implying the tree is visible, but because there's more fog between you and the tree, the optical depth is higher. Finally, there may be a tree 10 meters away with so much fog between you and the tree that the optical depth is $\tau = 1.5$. You can't see this tree because there's too much fog in the way. Hopefully you now realize that anything which is at a distance where $\tau > 1$ is not visible to you. That effectively defines a "surface" around you precisely when $\tau = 1$. Anything beyond that point is not visible and anything closer is visible.
If you're talking about the Sun, you can look at the Sun, but you'll only see light which originates from a point where $\tau < 1$. There are countless photons bouncing around inside the Sun, but you can't see them because they're in an opaque part of the Sun. Astronomers use the optical depth as a metric for defining the "surface" of the Sun.
The following is multiple choice question (with options) to answer.
If a handheld cylinder is allowing people to see in the forest after dusk, then the item likely | [
"needs a blanket",
"is a stone",
"hooks to outlets",
"uses knitting needles"
] | C | a flashlight requires a source of electricity to produce light |
OpenBookQA | OpenBookQA-3825 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
The population of plants will go down if | [
"nobody cuts them down",
"the people leave them alone",
"the rabbits avoid them",
"there's less liquid around"
] | D | as available water decreases , the population of plants will decrease |
OpenBookQA | OpenBookQA-3826 | cc.complexity-theory, big-picture, physics
Title: Energy considerations on computation In order to check my understanding, I would like to share some thoughts about energy requirements of computation. This is a follow up to my previous question and might be related to Vinay's question about conservation laws.
It occourred to me that, from a thermodynamical point of view, running a computation can be considered, to some extent, analogue to moving a weight along an horizontal line: The only energy loss is due to frictional forces, which can be, in principle, made arbitrarly small.
In an ideal setting without dissipative forces (the mechanical analogue of a reversible
computer), no energy expenditure is required at all. You still have to supply energy in order to accelerate the weight, but you can recover it all when decelerating it. The running time can be made arbitrarly small by investing enough energy (more precisely, if relativity is taken into account, running time is bounded from below by $d/c$, where $d$ is the distance).
Similarly, a reversible computer requires no energy expenditure but an energy investment that is recovered at the end of the computation, and running time can be made arbitrarly small by investing enough energy, up to relatvistic limits (as described in http://arxiv.org/abs/quant-ph/9908043 by Seth Lloyd).
There is, however, and energy cost associated with the construction of the computer. In general, this will depend on the implementation details, but I conjecture that we can state a lower bound for it:
Assume that our computer has three (classical or quantum) registers: Input, Output and Ancilla.
The Input and Output registers can be read and written to by the user, while the Ancilla register is inaccessible.
At the begining of each computation, the Ancilla register starts in a fixed (e.g. all zeros) state, and by the end of the computation it will have returned to the same fixed state. Thus, barring external noise, the Ancilla state needs to be initialized only once, when the computer is built.
The following is multiple choice question (with options) to answer.
What requires energy to move? | [
"a rock",
"a cloud",
"a monkey",
"a leaf"
] | C | an animal requires energy to move |
OpenBookQA | OpenBookQA-3827 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
In the food chain process an animal has the role of consumer which eats producers for what? | [
"grass",
"sea",
"water flow",
"sustenance"
] | D | In the food chain process an animal has the role of consumer which eats producers for food |
OpenBookQA | OpenBookQA-3828 | evolution, botany, photosynthesis, speculative, chloroplasts
Title: Why do plants have green leaves and not red? I know plants are green due to chlorophyll.
Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light has more energy than red light.
Is there no alternative to chlorophyll? Or is it something else? Surely it would be even more beneficial for plants to be black instead of red or green, from an energy absorption point of view. And Solar cells are indeed pretty dark.
But, as Rory indicated, higher energy photons will only produce heat. This is because the chemical reactions powered by photosynthesis require only a certain amount of energy, and any excessive amount delivered by higher-energy photons cannot be simply used for another reaction1 but will yield heat. I don't know how much trouble that actually causes, but there is another point:
As explained, what determines the efficiency of solar energy conversion is not the energy per photon, but the amount of photons available. So you should take a look at the sunlight spectrum:
The following is multiple choice question (with options) to answer.
For what purpose does a plant light serve? | [
"Mimic sunlight",
"Comfort them",
"Keep plants cool",
"Protect from bugs"
] | A | warm-weather organisms live in warm climates |
OpenBookQA | OpenBookQA-3829 | plate-tectonics, crust, mantle, cavern
Title: How likely are caverns inside the mantle? Almost everyone wrongly assumes that the Earth's mantle is liquid, but it isn't (only the outer core is). Is it possible then that there are hollow spaces within the mantle, similar to caves in the crust? What could they look like and up to how much of the mantle could be hollow? What might be inside mantle caverns? Would they be filled with gas or rather vacuum? It is extremely unlikely that any hollow volumes exist in the mantle.
The mantle is a convecting solid which can deform over long timescales. Let's assume that such a cavern did somehow form. Whatever it is filled it, would be of lower density than the surrounding rock. It would slowly rise upwards through the solid-yet-deformable mantle until it reaches a place where the rocks are brittle, not ductile. That place is the crust. And as you know, the crust is full of caverns and there is no problem with that.
The following is multiple choice question (with options) to answer.
If things are deposited consistently in dark, cavernous area, then a thing that could develop is | [
"apple juice",
"a stalactite",
"road rash",
"blue jeans"
] | B | stalactites are formed by deposition |
OpenBookQA | OpenBookQA-3830 | thermodynamics, heat, microwaves
Title: Microwave oven heating time It's logical to think that the time it takes a microwave to heat the food would be proportional to the mass heated. But since a microwave is based on dielectric heating, I think that if you increase the mass of food there will be more water, which will heat the food faster (due to thermalization). Is this reasoning right?
Is there an optimal quantity of food to heat and the time it takes? Good question. The rate of temperature increase scales as the power absorbed by the food divided by mass of the food. So to understand your question, you need to understand how power is absorbed.
There is a finite amount of power in the microwaves being produced. These microwaves bounce around in the metal cage where you put your food, until they come into contact with the food. (Well, some of them will get absorbed in the metal by imperfect reflection, but let's ignore that at first.) Once they get absorbed by the food, they turn into heat. Because they bounce around until they hit some food, the efficiency of a microwave is pretty high, in the sense that most of the power generated in the form of microwaves goes into heating the food, regardless of how much food you have.
So, at lowest-order, increasing the mass will increase the amount of water, but won't increase the amount of power being absorbed by the food. But now, that thing about absorption by the metal comes in. The power absorption will be slightly greater with a lot of food, since the food will be more likely to absorb the microwave before it gets absorbed by the metal. This is a lower-order effect, but it's there.
Of course, then the issue of skin depth comes in. Microwaves only penetrate a certain distance into the food. (Of order an inch, depending on the food.) So increasing the mass isn't really what you want; you want to increase the mass that's within the skin depth. For example, a wide dish of water that's one inch deep will absorb better than a jug of water with the same volume. This is why you want to split apart chicken breasts when defrosting them, for example.
The following is multiple choice question (with options) to answer.
If food is cooked what kind of energy is added to it? | [
"solar",
"cold",
"hotness",
"freezing"
] | C | if food is cooked then heat energy is added to that food |
OpenBookQA | OpenBookQA-3831 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
A bee is a pollinating | [
"moving alive thing",
"rock",
"tree",
"song"
] | A | A bee is a pollinating animal |
OpenBookQA | OpenBookQA-3832 | evolution, zoology, eyes
Title: Do other animals suffer from myopia or hypermetropia? Mammals have eyes similar to humas and many other animals like octopuses have a lens in the eye. So do they have such eye defects? If yes, how do they overcome it? Do they feel selection pressure against them in such cases?
do they have such eye defects?
Yes, eye defect is not specific to humans of course. Cases of eye defect are very common in animals. It is most often witnessed in domestic animals and they are the ones we observe the most (see The physiology of domestic animals)
Eye defects have typically been observed in tree shrews, monkeys (incl. macaques), cats, dogs, horses, rats, elephant and a Cape buffalo.
You should have a look at the wikipedia article Myopia in animals
howw do they overcome it?
They don't wear glasses obviously!
Humans uses the sense of vision a lot. Many animals uses smell (and taste), hearing or touch much more than humans do. For such non-visual animal, having a slight eye defect is not too big of a deal.
Do they feel selection pressure against them in such cases?
That is a bit of an awkward question. Nobody can feel a selection pressure on themselves. A selection pressure is a fitness differential associated with genotypes. A selection pressure is therefore defined at the population level. There is no such thing as a fitness pressure against a single individual.
Let me rephrase this last question to something that makes more sense. I am not sure I will address the specific question that was of interest to you though.
Are non-humans animals that have an eye defect aware that they have an eye defect?
It is unlikely that any animal would have the cognitive abilities to notice that they see more poorly than another animal of the same species. Doing so, would at least require having the ToM and only few species do.
The following is multiple choice question (with options) to answer.
If a creature is looking for things but is using something other than its eyes or nose, then it is likely | [
"condensing",
"echolocating",
"reproducing",
"revolving"
] | B | echolocation is when some animals detect objects by hearing echoes by emitting sound |
OpenBookQA | OpenBookQA-3833 | evolution, ornithology, palaeontology
One thing those many, many bird and proto-bird fossils also made clear is that the traits of modern birds (feathers, wings, toothless beaks, etc) didn't evolve in a simple line from non-bird to bird. Many of those traits evolved convergently in several lineages, were lost in some, maybe regained in others, and feathers in particular turn out to be a widespread dinosaur feature that cannot be considered a uniquely bird trait anymore (unless we want to call T-rexes "birds"). Still, saying "beaks evolved several times" or "feathers evolved several times" doesn't mean that birds, let alone modern birds, evolved from several different ancestors. It can mean that the common ancestor of birds had lots of variously bird-like more-or-less distant cousins living around the same time.
The following is multiple choice question (with options) to answer.
Toucans' beaks are for show but also can be used for | [
"toasting",
"coloring",
"dancing",
"skinning fruits"
] | D | birds with beaks of different shapes eat different foods |
OpenBookQA | OpenBookQA-3834 | cc.complexity-theory, graph-theory
For general connected cubic graph decomposition problems, under which conditions does the existence of a non-decomposable graph imply the $NP$-completeness of the decomposition problem?
EDIT For the second question, Is there a subclass of connected bridgeless cubic graphs where non-decomposable graphs exist but it is polynonial time to decide the existence of a (edge) decomposition?
The linked post on MthOverflow provides some interesting examples of connected cubic graph decomposition problems.
EDIT The problem is posted on MathOverflow: Connection between Barnette conjecture and hardness of cubic graph decomposition As pointed out by David Eppstein when I asked a related question a while ago: you can do that in polynomial time.
The idea is to find a perfect matching $M$ (which exists and can be found in polynomial time since your graph is cubic and bridgeless), and then to use the edges of $M$ as middle edges of the $P_4$'s.
To complete the construction, remove the edges of $M$ and orient the remaining cycles arbitrarily. Then attach to each edge $\{u, v\}$ of $M$ the arcs going out from $u$ and $v$, and you are done.
The following is multiple choice question (with options) to answer.
Which of the following is an example of decomposition? | [
"a dog eating dog food",
"something growing on a dead tree trunk",
"a lion eating a gazelle",
"a parrot eating bird seed"
] | B | decomposition is when a decomposer recycles nutrients from dead organisms to the soil by eating those dead organisms |
OpenBookQA | OpenBookQA-3835 | entomology, biophysics, hearing
$^1$ Bennet-Clark and Young, The Role of the Tymbal in Cicada Sound Production, J. of Experimental Biol. (1995) 198, 1001-1019.
$^{2}$ The frequency of cicadas is variable, mostly on the order of 10kHz but occasionally very low (< 1kHz), mostly due to body size. See this article.
$^3$ Sound--essentially a compression wave--diminishes with distance. So when the Wiki article on noise levels compares noise levels it includes the distance from the object. For example, 100 db (comparable to the cicada) is the level of noise associated with a jack-hammer at 1 meter away.
$^4$ Audible range for humans is roughly 15 Hz-16000 Hz. As mentioned below, the dolphin can emit very intense high-pitched sounds that we don't hear at all, so the analogy to EM waves (higher frequency = higher energy) doesn't help predict perception. See Pfaff and Stecker, Loudness and Frequency Content of Noise in the Animal House, Lab. Animals (1976) 10, 111-117.
$^5$ M. Versluis, B. Schmitz, A von der Heydt & D. Lohse (2000). "How snapping shrimp snap: through cavitating bubbles". Science 289 (5487): 2114–2117.
$^6$ Bennet-Clark and Young, Short Communication, The Scaling of Song Frequency in Cicadas, J. Exp. Biol. 191, 291-294 (1994).
The following is multiple choice question (with options) to answer.
Sound pulses helps dolphins | [
"satisfy women",
"find God",
"find nourishment",
"find ibexes"
] | C | the ability to find resources has a positive impact on an organism 's survival |
OpenBookQA | OpenBookQA-3836 | everyday-chemistry, food-chemistry
Title: Why does pasta really boil over? I was making pasta, and I noticed the pasta boiling over. I thought about it some more, and I realized I had no idea why this was happening. When the lid is on, the foam rises. When the lid is off, the foam dies back. Clearly there's some surfactant at work allowing bubbles to form, and the bubbles are mostly full of steam. If you remove the lid, they cool and condense down to a tiny size. This article is honestly just not specific enough. Why is the starch important?(It also happens with potatoes) How does a polysaccharide, a hydrophilic molecule, become a surfactant(if indeed it does)? Is it phospholipids from the cells that became pasta? Do starch molecules form a polymer and trap steam underneath like a balloon? Is it some kind of hybrid where bubbles are stabilized by viscosity? What's going on here?
This question on seasoned advice tries to tackle it but gets surface tension wrong(I think) so that makes me a little wary of it. Surfactants like soap reduce the surface tension, allowing bubbles to form by letting water molecules spread out into thin films. They also keep your alveoli in your lungs from collapsing. If starches increased the surface tension, wouldn't that reduce the likelihood of forming bubbles by increasing the energetic penalty? High surface tension materials act like mercury.
This answer is all over the internet but doesn't make any sense to me. You need less surface tension for bubbles, surely?
If it's just phospholipids acting as detergent, could I 'boil over' pasta in cold water with a whisk? (I tried this, you can't.)
I considered putting this on seasoned advice, but I'm not interested in how to prevent boil-over(or really any practical results), and the supplied answer there lacks scientific rigor. The starch forms a loosely bonded network that traps water vapor and air into a foamy mass, which expands rapidly as it heats up.
Starch is made of glucose polymers (amylopectin is one of them, shown here):
The following is multiple choice question (with options) to answer.
Dropping butter into a boiling water would cause it to | [
"hoover",
"grow",
"liquefy",
"refreeze"
] | C | melting means changing from a solid into a liquid by adding heat energy |
OpenBookQA | OpenBookQA-3837 | design
Title: Design of atomic bomb Please see the following photo. (I cannot post it)
http://i1163.photobucket.com/albums/q554/startanewww/CIMG4548.jpg
Why is atomic bomb in a "fish-like" shape? (I don't know how to describe it) Is it specially designed for some purposes?
Thanks a lot. The diagram looks like the Fat Man bomb that was dropped on Nagasaki. The Wikipedia article gives lots of info on the design if you're intereted in pursuing it further.
The casing is just to make it aerodynamically stable so it fell in a controlled way. The bomb itself is spherical so the case could be spherical as well if it weren't for aerodynamic requirements.
The following is multiple choice question (with options) to answer.
Japan made Pearl Harbor | [
"the sky",
"it's victim",
"the moon",
"boring and empty"
] | B | An example of hitting something is dropping an object onto that something |
OpenBookQA | OpenBookQA-3838 | optics, astronomy, reflection, metals, telescopes
I used a good lens, which is why the effect is so small, but this shows the principle behind it.
Exhibit D
This is a microwave door - it is opaque to microwaves, but as you can see, lets visible light through. (See Faraday Cage)
Exhibit E
WiFi. It can pass through walls and doors.
It should be clear now that light doesn't exactly behave like what our brain calls "light"
Finally
I hope this helps. As you can see - WAAAY to long for a comment.
The following is multiple choice question (with options) to answer.
light can travel through | [
"trees",
"rocks",
"matterless places",
"rubber"
] | C | light can travel through a vacuum |
OpenBookQA | OpenBookQA-3839 | infection, amphibians
Title: What is this toad suffering from? Myiasis or chytridiomycosis? I found this toad on Aug. 29th at this location: position on osm
I think it is a bufo bufo, approx. 10 cm long. The nostrils seemed to be completely filled with a grey matter and from the activity of the floor of the mouth it apparently tried to breathe againgst this obstruction. It probably had enough oxygen via its skin though.
I tried to remove the obstruction using a blade of grass but this seemed to produce some pain as the toad closed its eyes on contact, so I stopped. The skin looked fairly normal and the toad was able to walk away after a while.
I can think of two causes for this condition.
Batrachochytrium dendrobatidis infestation
Lucilia bufonivora larvae
I could not see properly, if there were any larvae or unhatched eggs inside the nostrils, but as the rest of the skin seemed unharmed I assume the latter.
Is my assumption valid or is there even a third possibility? It is a female Bufo Bufo and you are right, there are toad fly (Lucilia bufonivora) larvae/eggs inside her nostrills. These flies lay their eggs inside toads' nostrills (specifically on Bufo Bufos) and the larvae start eating them. Sadly this disease ends up by the death of toad. They slowly eat nostrills, then mouth, eyes, and all the head.
Here's a photo of a male bufo bufo, without a head. Someone found it walking around at this situation. https://i.stack.imgur.com/I6twl.jpg
The following is multiple choice question (with options) to answer.
if a person found a toad in the water, where else would it normally be? | [
"it would be on the ground",
"it would be in the air",
"it would be in the sea",
"it would be in a volcano"
] | A | adult amphibians live on land |
OpenBookQA | OpenBookQA-3840 | thermodynamics, gravity, mass
This makes the math easy. Since the person's velocity is the same at the start as it is at the end, 100% of the gravitational potential energy goes into drag, which eventually becomes heat. The gravitational potential energy at the top is $PE=mgh$. Mass is 68kg, g is 9.89m/s2, and h is 828m, for a total of 0.5MJ per fall.
Now we just plug this back into $E=mc^2$ to get a mass of 0.000000000005563kg.
We're going to be here a while. To burn off 34kg at that rate will take 6,000,000,000,000 falls, each lasting 15 seconds for a total of 2,905,135 years of falling.
And I'll note I'm handwaving away something very important. Your portal is providing exactly the same amount of energy into the person during the teleport, and we're not accounting for it.
But, regardless, the reality is that the relativistic mass losses are so slight that our human will decide infinite portal falling is no fun long before we start to see measurable mass losses.
And, given how difficult it would be to get them food during that time, this would also qualify as the ultimate weight loss program... at least while they are still alive.
Indeed, I do think that if we take this vertical situation, and rotate it to be horizontal, we've seen it before.
The following is multiple choice question (with options) to answer.
Someone stranded in the Sahara can potentially save their life with a | [
"dried plant",
"prickly plant's trunk",
"water buffalo",
"dead cactus"
] | B | a cactus stem is used for storing water |
OpenBookQA | OpenBookQA-3841 | newtonian-mechanics, forces, rotational-dynamics, friction, free-body-diagram
Title: How does friction stop a car? I'm unable to understand how friction causes motion in cars and also is responsible for stopping them.
When it starts the impending motion of tyres is in the backward direction that's why friction is in the forward direction and the car starts moving.
But when the car engine turns off, the car stops after some time, but the condition of tyres are the same as in the previous case and friction must be in the forward direction. It is not the same friction, but rather the friction between the wheels and the breaking pads (and in general between the rotating parts of the car and their supports.)
The following is multiple choice question (with options) to answer.
friction is used for stopping a vehicle by | [
"running",
"singing",
"smelting",
"squeezing"
] | D | friction is used for stopping a vehicle by brakes |
OpenBookQA | OpenBookQA-3842 | atomic-physics, geophysics, explosions
I think the most interesting diagrams are the ones labeled (e) and (f) - where the explosion happens at great depth. In that case, you get a "tight packing" of the soil above in a way that I think is similar to the mechanism that causes sugar to "settle" if you first fill a bowl to the rim, and then tap the bowl gently. The shock wave that travels through the soil (or the sugar) causes individual grains to find a more energetically favorable orientation - so they are a little more tightly packed. This can result in a crater.
Now whether you consider this "compacting voids" is a matter of opinion. But it's a real effect. Of course, very close to the nuclear reaction the heat will be so great that the rock will liquify; as a liquid it might be able to pack more tightly, although that depends on many factors.
The following is multiple choice question (with options) to answer.
The objects the push up through the deep black stuff that covers the ground gives us an item that is inserted in a sweet treat with a flaky bottom of flour that can be eaten with ice cream on top? | [
"Leafs",
"Eggs",
"Milk",
"Fruit"
] | D | plants are the source of fruit |
OpenBookQA | OpenBookQA-3843 | zoology, digestive-system, pets
Title: Is it safe to feed an adult fire salamander with slime maggots? As a reminder, maggots feed of a flesh, while fire salamander consumes his prey alive, without killing it.
Can it happen that the maggot will start eating the salamander from the inside? Although I am afraid I don't know much about fire salamanders specifically, it is certainly possible for ingested fly larvae (or larvae hatching from ingested eggs) to survive ingestion and subsequently cause intestinal damage. Parasitic infestation by fly larvae that grow inside the host while feeding on its tissue is called myiasis. Enteric myiasis (also called gastric, rectal, or intestinal myiasis to indicate the affected part of the digestive system) occurs occasionally in humans following the ingestion of cheese infested with cheese fly maggots. Casu marzu, a traditionally produced Sardinian cheese, is supposed to have live cheese fly maggots in it, and cases of bloody diarrhoea following its consumption are known. If they're dead the cheese is considered unsafe to eat (although personally I'd correct that to 'more unsafe').
The following is multiple choice question (with options) to answer.
Maggots eat flesh turning it into | [
"dryer",
"nourishment for soil",
"rancid",
"deadlier"
] | B | decomposition increases the amount of nutrients in the soil |
OpenBookQA | OpenBookQA-3844 | fluid-dynamics, flow
Title: Where does the air go behind a wind turbine? A wind turbine receives wind at 10m/s, and slows it to 5m/s to generate electricity.
Does this mean that the wind around the turbine must be diverted to allow twice the cross-section area for the exiting wind?
If not, how does the exiting air escape? To preserve continuity of mass flow across the propeller disc, the slower air exiting the disc downwind swells out to produce a slow-moving wake that is wider than the propeller disc itself. This gets mixed up with the surrounding air and eventually the wake dissipates as the air in it speeds up to match the surrounding velocity.
The following is multiple choice question (with options) to answer.
Another term for wind energy is clean energy because the wind and air contains | [
"Seven",
"under energy",
"zero pollutants",
"moon"
] | C | a windmill does not create pollution |
OpenBookQA | OpenBookQA-3845 | geophysics, sedimentology
Title: Does dirt compact itself over time? If so, how does this happen? If I were to bury something 10 feet (~3 metres) underground, with loose soil on top, would the ground naturally compact itself over time, until whatever I had buried has dirt tightly pressing against it on all sides?
What if I buried it 50 feet (~15 metres) underground?
If it exists, what is this compaction process called and how does it happen? Soil is a collection of various sized minerals grains, of various types of minerals produced by the weathering of rock. Typical soil minerals are clays, silts and sands.
The properties and behavior of different soil types depends of the composition of the soil: the proportion of clays, silts and sand in a soil. Sandy soils are well draining and clayey soils are sticky.
Between the grains of minerals that comprise a soil are spaces, called pores or pore spaces. The pores can be filled with either water or air, depending the location of water tables and wetting events like rain, snow melts or other forms of water inundation.
The density of a soil is dependent on the degree of compaction of the soil. For to a soil to be compacted, a stress has to be applied to the soil to realign the grains of soil which reduces the total volume of the pores and reduces the amount of air within the pores.
Consolidation of a soil occurs when pore space is reduced and water in a soil is displaced due to an applied stress.
Regarding having something buried and soil compacting around it over time, yes that will occur but it is a question of how much stress the soil experiences, the duration of time and the nature of the soil - sandy or clayey. Something buried for a day without any stresses not much will happen. But, something buried for thousands of years with people and animals walking over it, rain falling on the soil, vibrations from nearby human activity and an occasional earthquake all add to the stresses the soil will experience and increases the degree of compaction or consolidation over time.
The following is multiple choice question (with options) to answer.
What loosens soil? | [
"iron",
"boring",
"metals",
"sunlight"
] | B | tunnels in soil loosen that soil |
OpenBookQA | OpenBookQA-3846 | c#, object-oriented
}
Purge class:
public class ThrottlerPurger : IThrottlerPurger
{
private readonly IThrottlerCollection throttlers;
private readonly ILogger logger;
private readonly Timer timer;
public ThrottlerPurger(IThrottlerCollection throttlers, ILogger logger)
{
if (throttlers == null) throw new ArgumentNullException("throttlers");
if (logger == null) throw new ArgumentNullException("logger");
this.throttlers = throttlers;
this.logger = logger;
timer = new Timer(x => Purge());
}
public void StartAsyncPurge(int startWhenInMs, int recurWhenInMs)
{
timer.Change(startWhenInMs, recurWhenInMs);
}
public void StartAsyncPurge(TimeSpan startWhen, TimeSpan recurWhen)
{
timer.Change(startWhen, recurWhen);
}
public void StopAsyncPurge()
{
timer.Change(Timeout.Infinite, Timeout.Infinite);
}
public void Purge()
{
Dictionary<string, IThrottler> toRemove = null;
lock (throttlers)
{
foreach (var throttler in throttlers)
{
if (throttler.Value.IsIdle || !throttler.Value.IsAlive)
{
if (toRemove == null) toRemove = new Dictionary<string, IThrottler>();
toRemove.Add(throttler.Key, throttler.Value);
}
}
if (toRemove == null) return;
foreach (var throttler in toRemove)
{
throttlers.Remove(throttler.Key);
logger.LogInfo("Purged {0} {1} throttler.", throttler.Value.IsAlive ? "idle" : "dead", throttler.Key);
throttler.Value.Stop();
}
}
}
The following is multiple choice question (with options) to answer.
If a person has an unwanted raccoon rifling thru their trash they should | [
"be sure to keep their trashcan tightly closed and secured",
"leave more scraps out for the raccoon",
"be sure to put out some water so the raccoon is super healthy",
"put loose food scraps in the trashcan"
] | A | if the amount of available food and water decreases in an environment then animals may leave that environment to find food and water |
OpenBookQA | OpenBookQA-3847 | physical-chemistry
Title: why cookware does not melt down? why cookware does not melt down
On stove supllied with butane gas which has a flame temperature of 1970°C?
http://www.engineeringtoolbox.com/flame-temperatures-gases-d_422.html Cookware has a large surface area and radiates heat. Also conducts heat to water or food it is in contact with. You reach a steady state at some temperature that is less than the melting point.
If you used a small piece of metal, you might get some melting. For example, if you put a post-1983 penny on your burner, you can probably metal the zinc inside to form a brass alloy.
The following is multiple choice question (with options) to answer.
A hot stove can burn | [
"the sun",
"a stone monument",
"your elbow",
"diamonds"
] | C | if a body part was burned then that body part was exposed to a lot of heat energy |
OpenBookQA | OpenBookQA-3848 | sexual-reproduction
So when it's not maintained -- when there's no selection pressure on two populations -- inevitably there will be genetic drift that will randomly disrupt this fine-tuned system. If a population of, say, voles is isolated on an island, they will continue to have pressure to be able to interbreed with other voles on the island, but if they can't interbreed with those on the mainland there won't be any consequences, and so over long enough time they'll drift and lose that ability -- just as many apes, not suffering any consequences from not synthesizing vitamin C, gradually lost that ability from random drift.
There's another side to it. Two populations in the same location may be positively selected to not be able to interbreed. Think about two groups of finches, one with small fine beaks that eat tiny seeds deep inside pine cones, and one with heavy beaks that crush and eat thick-shelled nuts. They each do fine, but they can interbreed and produce offspring that have intermediate beaks -- too thick to reach the fine seeds that one parent eats, but too delicate to crush the nuts that the other parent eats. Those intermediate offspring will die off, and both parents will have wasted their resources raising them. Both parents would be better off not breeding with each other, but only breeding with their own kind to produce specialized and efficient offspring. There is now selection pressure on the birds to recognize their own kind (perhaps through songs or mating displays) and ultimately to be inter-sterile, so they never waste resources on the un-fit offspring. There's a gradation of separation over time, in which the different populations become more and more distinct. Eventually, at some arbitrary point, humans start calling them "species", but that's just us, not biology.
"Species" is an important concept, but it's not special in evolution; speciation is just one aspect of natural selection, there's nothing magical about it.
The following is multiple choice question (with options) to answer.
What can reproduce | [
"Spoon",
"Keyboard",
"Deceased cat",
"Living dog"
] | D | living things can all reproduce |
OpenBookQA | OpenBookQA-3849 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
Jackrabbits live in very hot environments, but are able to stay cool because their long ears help | [
"releasing warmth",
"sing songs",
"make eggs",
"change tires"
] | A | long ears are used for releasing heat by a jackrabbit |
OpenBookQA | OpenBookQA-3850 | botany, species-identification, entomology
Title: What is this tiny thing on the branch I noticed a tiny spot with weird shape on the shoot of a plant (Variegata), and there are many others on other branches. I wonder what is it, this is a cropped picture of it, Thank you!
This is a female of yet another scale insect (Coccoidea). We have discussed one recently.
I guess we can identify this one rather precisely as Ceroplastes sinensis or its close relative. Species of this group are of South American origin, but Ceroplastes sinensis has today an extremely broad distribution. So, if you found this plant ("Variegata" is a specific epithet, by the way: it would be of some help if you provided the generic name as well) in Europe or Asia it's likely sinensis itself.
The following is multiple choice question (with options) to answer.
The smallest known species of cactus, called Blossfeldia Liliputana, is named after | [
"The Hobbit characters by J. R. R. Tolkien",
"a fictional island in Gulliver's Travels by Jonathan Swift",
"Frodo Baggins from Lord of the Rings",
"Bilbo Baggins from Lord of the Rings"
] | B | a cactus stores water |
OpenBookQA | OpenBookQA-3851 | mechanical-engineering, manufacturing-engineering, cnc
What minimum documentation of 'know how' should be provided for such a project, making complex mechanical parts out of aluminium?
Depends on what you mean by "minimum".
You could argue the drawing is the minimum...a bit lacking though if it doesn't have tolerances specfied and such. Just add process design experience.
Then there is the process manual which details the step-by-step the tooling and operation to be performed on the part, intermediary drawings, and tolerancing. Not cheap to develop, and also specific to the equipment you have available, but also not necessarily the only way to make to a part and not something you leave laying around. Used in industries like aerospace. I've been told each part actually has an its own copy of the manual following it around where the measurements after each process are filled in and signed off on.
The following is multiple choice question (with options) to answer.
A stage in the life cycle process includes what aspect? | [
"killing of kin",
"entity replication",
"transporting water",
"reproducing ideas"
] | B | adulthood is a stage in the life cycle process |
OpenBookQA | OpenBookQA-3852 | food, alcohol, bacterial-toxins, parasitism, decomposition
So, in conclusion: It's what happens inside the meat that counts. If you bathe meat in ethanol, a useful amount of ethanol may permeate the meat. The freezing point of the meat (rather, the aqueous solution within it) will be lowered the more ethanol perfuses it. In theory, you could even drop that freezing point below that of ethanol itself, but it would require replacing nearly all of the water with ethanol.
The following is multiple choice question (with options) to answer.
If a person is running a salad bar and needs to keep the bar cold, and therefore the ice frozen, they might | [
"pour sodium over the ice",
"put the ice in the sun",
"melt the ice on a stove",
"throw the ice away"
] | A | adding salt to a liquid decreases the melting point of that liquid |
OpenBookQA | OpenBookQA-3853 | agriculture
Title: What does "permanent field" mean in agriculture? I am reading a book that in a paragraph talks about the agricultural methods used in prehistoric Finland.
The further north and east, the more extensive the amount of
burn-beat cultivation, which was a far from primitive form of
agriculture. The yield was many times higher (twenty- to thirty-fold)
than on permanent fields (five- to ten-fold), and there were multiple
varieties of the technique
A history of Finland by Henrik Meinander.
One of them is burn-beating. Like I understand, in burn-beating people cut down the trees in the forests and burn the topsoil. This way they can use that soil for 3 to 6 years for cultivation.
The other method is permanent field. I have searched the internet and the result I got was "permanent crops", like here. In which case people planted trees once in a field and harvested them multiple times.
But in another research about prehistoric Finland it was saying:
The site of Orijärvi shows that permanent field cultivation, with
hulled barley as the main crop was conducted from approximately cal AD 600 onwards.
The following is multiple choice question (with options) to answer.
over a period of three years, a farmer cultivates, corn, millet and potatoes. What is this exemplary of? | [
"An amateur farming practice",
"a way to gain attention",
"a manner of rotating",
"a way to confuse spectators"
] | C | crop rotation is when different crops are planted on a field in different years |
OpenBookQA | OpenBookQA-3854 | civil-engineering, building-design
Title: Is it OK for a 2 story house not have a column or pillar sorry for my english. I was looking to buy a house. I saw some in my hometown, which is very affordable.
but on a picture of the house they are selling I found on the net troubled me.
no pillar/column, just hollowblocks and some steel bars.
kindly look at the pic.
I found it in this site
https://fiestacommunitiesblog.wordpress.com/tag/fiesta-communities/ As @SamFarjamirad states it's best to consult a knowledgeable construction engineer where you live, or in your region, because such people would know the building codes & construction practices for your region. A column or pillar for a two storey house may not be necessary if the load bearing walls are designed & built properly. This may include internal load bearing wall, inside the house. The other thing to be wary of is the quality of the foundations for the load bearing walls. Also, if the house to be renovated later all load bearing walls must not be removed or altered.
It looks like the steel is being threaded through the hollow block in the external walls. This would be done to increase the flexibility of the house during earthquakes and should a typhoon/cyclone/hurricane affect the house. Internal load bearing walls should also have such steel reinforcement.
If designed and built correctly such steel reinforced walls should not collapse. They might crack during extreme natural events but they should not fall and collapse the house.
Looking at the picture you included, some things that I found strange were:
The following is multiple choice question (with options) to answer.
You may need a raft after a | [
"television broadcast",
"drought",
"meteor shower",
"deluge"
] | D | heavy rains cause flooding |
OpenBookQA | OpenBookQA-3855 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
Of these, a wolf will make its home very nearest to | [
"mink",
"humans",
"lions",
"whales"
] | A | most predators live near the same environment as their prey |
OpenBookQA | OpenBookQA-3856 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
What would a squirrel like for nutrition? | [
"safe plants",
"insects",
"worms",
"poisonous plants"
] | A | squirrels eat edible plants |
OpenBookQA | OpenBookQA-3857 | species-identification, zoology, marine-biology, ichthyology, bone
Title: Identification of a strange skull My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it? Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site).
I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is indeed a neurocranium.(source of the picture).
Thank you all for your help!
The following is multiple choice question (with options) to answer.
if a salmon visits the site of its birth, what could be the reason for that? | [
"it is coming to have its own offspring",
"it is coming home to die",
"it is coming to see its father",
"it is coming to visit its mom"
] | A | An example of a reproductive behavior is salmon returning to their birthplace to lay their eggs |
OpenBookQA | OpenBookQA-3858 | ocean, ocean-currents, tides
Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.
The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals) and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.
A good review of possible effects on benthic organisms is provided by Shields et al (2011). These may include,
The following is multiple choice question (with options) to answer.
Which likely provides a neutral effect to local organisms? | [
"asteroid impact",
"habitat destruction",
"9.0 earthquake",
"stormy weather"
] | D | An example of stormy weather is rain |
OpenBookQA | OpenBookQA-3859 | reproduction, asexual-reproduction
Title: can self-fertilization in flowers be called asexual reproduction? Suppose a flower having both male and female reproductive parts is self-fertilized then can this be called asexual reproduction...?I'm quite confused cause in this case the fusion of male and female gametes do take place but again the gametes are from the same parent....please help. According to this article from Berkeley, asexual reproduction is:
Any reproductive process that does not involve meiosis or syngamy
Using this definition of asexual reproduction and knowing self-fertilization involves meiosis and syngamy, it is not asexual.
The following is multiple choice question (with options) to answer.
Reproduction produces what? | [
"energy",
"younglings",
"flames",
"water"
] | B | reproduction produces offspring |
OpenBookQA | OpenBookQA-3860 | electromagnetism, magnetic-fields, electromagnetic-induction, batteries
Title: How this toy shown on YouTube works and can the coil be replaced by a hollow magnetic thorus? I saw this video on YT and what I can not figure out is why the coil used in the arrangement could not be replaced by a hollow magnetic torus? Notice that the magnets are attached to the ends of a battery (the source of power). To experience a net force, the magnets must be in a non-uniform magnetic field. In this case the magnets conduct current, to the coil, which flows only between the magnets. A short segment of hollow magnetic torus produces a field which spreads rapidly at the ends and thus exerts a force on the magnets which are at each end of the energized segment. One would need to be careful that the magnets are oriented so that both forces are in the same direction. In this system, the current is mainly limited by the internal resistance of the battery, and may be relatively large. The battery will be drained quickly. A magnet acts as though it has a current flowing around its outer surface. If we take a side view and assume that the field from the coil is spreading out from its right end (the “north pole”), and we place a magnet so that its current flows away from us on the top (putting its north pole on the left), then the vertical component of the field will push the current on top of the magnet to the right, and the current on the bottom will also be pushed to the right. (This kind of analysis can also be applied to the microscopic currents associate with each atomic dipole using the divergence of the field). On the left end of the activated section of the coil, the field is coming in, the vertical components are reversed, and to keep the net force to the right, the magnet would need to be reversed. If you think of both magnets as being just outside of the ends of the activated coil, the north pole of the magnet is being repelled by the north pole of the coil on the right, and the north pole of the magnet is being attracted by the south pole of the coil on the left. (A compass needle can be used to determine which ends are north or south.)
The following is multiple choice question (with options) to answer.
What will become magnetic in an electromagnet if the battery becomes active? | [
"A nail box",
"A construction nail",
"A plastic nail",
"A wooden nail"
] | B | non-contact forces can affect objects that are not touching |
OpenBookQA | OpenBookQA-3861 | the-sun, earth
Title: If the Sun got larger, but maintained its luminosity, would the Earth get hotter or colder? A recent question If the Sun were bigger but colder, Earth would be hotter or colder? asked - if the Sun got bigger and cooler, would the Earth heat up or cool down. I think the answer to that is mainly that it depends on the final luminosity.
However, what I want to know here (hypothetically), is if the Sun got larger and it's effective temperature decreased such that it's luminosity was unchanged; how would that affect the equilibrium temperature of the Earth? I suspect the answer may involve the wavelength dependence of the albedo, emissivity and atmospheric absorption of the Earth.
Another, less hypothetical, way of asking this is, if you put an Earth-like planet at different distances from stars with a variety of temperatures, such that the total flux incident at the top of the atmosphere was identical, how would the temperatures of those planets compare? The key issue is the opacity of the atmosphere, because I presume the question is about the temperature at the solid surface of the Earth. The atmospheric opacity can be seen from https://physics.stackexchange.com/questions/135260/can-someone-explain-to-me-the-concept-of-atmosphere-opacity, where you can see that the "rainbow" of maximum heat flux from the Sun happens to hit a kind of hole in atmospheric opacity. That has a significant warming effect on the Earth, and is exacerbated by the Greenhouse effect. If sunlight was further into the infrared, the graph shows that much more of it would be intercepted in the atmosphere. That would make the surface significantly colder, though certainly not a factor of 2 colder.
No doubt the question is of more than passing interest, because M dwarfs are the most numerous main-sequence stars and are therefore interesting for life. To have life near an M dwarf, the planet would need to be closer than Earth is to the Sun, but the effect of moving the planet closer and shrinking and cooling the star would be similar to leaving Earth where it is and making the star cooler and larger. So the nature of atmospheric opacity for wet atmospheres must be of great significance for understanding the prospects for life around M dwarfs.
The following is multiple choice question (with options) to answer.
Without the sun providing warmth and light, life on Earth would | [
"nothing",
"flying",
"an impossibility",
"Mars"
] | C | the sun is the source of energy for life on Earth |
OpenBookQA | OpenBookQA-3862 | newtonian-mechanics, forces, acceleration, inertia, jerk
Title: Bidirectional jerk motion on a stopping vehicle A stopping vehicle (say a car) has an apparent retardation (which may/may not be constant in magnitude) when force via brakes is applied.
I travel by subway trains, and I noticed an odd phenomenon. The thing about such trains (might be irrelevant) is that, being light-weight, their motion somewhat mimics that of cars, and the effects of motion are more apparent as one usually stands in such trains. The thing I noticed was that I could feel a force pulling me in the initial direction of motion, as the train slowed down. That obviously is the inertia. But as soon as the train halted, I noticed a secondary jerk...this time in the opposite direction, and it was kind of short lasting.
I'm curious to know, what causes this secondary jerk backwards as soon as a vehicle comes to rest. I'm guessing it has something to do with the reaction force by the brakes which overcome the forward motion and provide an impulse backwards. But then it has to have a proper force 'mirror' as per the third law of motion. Also, there never is any intentional backwards motion here (the drivers are precise, I guess).
So what could it really be? "Jerk" is indeed the correct term to describe both the experience and the cause, which is a (sudden) change in acceleration.
If the car decelerates at a constant rate, there is a constant force on you from the safety belt, to prevent you hitting the windscreen. If the car were to maintain the same deceleration when it had reached zero velocity then it would immediately start going backwards. However, the car does not move backwards. The deceleration changes from a constant value to zero in a very short time. But there is still a force on you from the springiness in the safety belt, which is under tension, throwing you back into the seat, which is no longer accelerating backwards. The force on you from the safety belt changes suddenly as you are flung back into the seat, as it did if the braking also started suddenly; the sudden change in the force on you is what causes the discomfort.
The following is multiple choice question (with options) to answer.
a man drives away from his dog, and the dog progressively got smaller in the rear view mirror. what was happening? | [
"the dog was evaporating",
"the distance between them remained same",
"the distance between them was going down",
"the distance between them was going up"
] | D | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-3863 | everyday-chemistry, experimental-chemistry
Title: Confusing definition of the term precision According to the textbook, we say a measurement is precise when series of measures are close to each other.
But in real use, I feel like the term is used in a different meaning.
For example, scale A weighs to cube of lead and displays 10.5g while scale B displays 10.4977g.
In this case, one say the measurement made by scale B is more precise than that of A. That is, scale B can distinguish more fine weights than A.
Isn't this usage of the word precise different from textbook definition? Please explain clearly the real usage of the term precise. In colloquial English, precision is synonymous with accuracy. If you look it up on Google, the first definition is:
the quality, condition, or fact of being exact and accurate.
In the field of science, however, it takes on another meaning:
the degree to which repeated measurements under unchanged conditions show the same results
There is also measurement resolution:
the smallest change [an instrument] can detect in the quantity that it is measuring
Which is similar to the definition precision takes on in numerical analysis:
the resolution of the representation, typically defined by the number of decimal or binary digit
In short, precision can take on different meanings depending on how you choose to apply it. If you talk about the precision in a set of measured data, you will be using the scientific definition; if you talk about the precision of an instrument, you will be using the numerical analysis definition.
The following is multiple choice question (with options) to answer.
A scale is used to measure what? | [
"location",
"heaviness",
"length",
"height"
] | B | a scale is used for measuring weight |
OpenBookQA | OpenBookQA-3864 | environmental-protection, natural-disasters
Title: The impact of red mud near Hamburg On October 4, 2010 a disaster started at a site in Ajka, Hungary. A red mud reservoir near an alumina plant broke, and the toxic material moved through nature and on into the northern half of Devecser village and killed 10 people, injured 406 others, and destroyed a lot of trees and animals.
I calculated the area of that reservoir to be about 25 hectares using this site.
Also, I calculated the maximum length and width of the flown red mud to be about 3 miles and 1 mile respectively (using Google Maps).
On the Wikipedia page for the Ajka disaster it's also stated that the volume of red mud was about 1,000,000 m$^3$, and the total area affected was about 40 km$^2$.
That got my attention looking at a red mud reservoir near Hamburg. It has an area of about 1.45 km$^2$, and it is 28 miles far from Hamburg. Also, it's near an alumina plant in Stade.
The following is multiple choice question (with options) to answer.
The everglades where nearly wiped out by | [
"the sun",
"builders",
"sea cows",
"alligators"
] | B | humans building homes in an ecosystem causes that environment to change |
OpenBookQA | OpenBookQA-3865 | Now we need to just pick two dogs for the first row so that remaining two dogs will be automatically be selected for other row = 4C2
Total ways = 8C4 * 4C2 = 70*6 = 420
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Re: Eight dogs are in a pen when a sled owner comes to choose four dogs to [#permalink]
### Show Tags
03 Oct 2017, 09:28
1
Bunuel wrote:
Eight dogs are in a pen when a sled owner comes to choose four dogs to form a sled team. If the dogs are to be placed in two rows of two dogs each and different pairings of dogs are considered different teams, how many different sled teams can the owner form?
A. 24
B. 70
C. 210
D. 420
E. 1,680
There are 8C4 = 8!/[4!(8-4)!] = (8 x 7 x 6 x 5)/4! = (48 x 7 x 5)/24 = 2 x 7 x 5 = 70 ways to choose 4 dogs from a total of 8 dogs. Once 4 dogs are chosen, let’s see how many pairings of two rows of 2 dogs are possible. Let’s say the 4 dogs are A, B, C, and D.
The following is multiple choice question (with options) to answer.
If a dog is hunting, then | [
"it can sense whales nearby",
"it can sense toys around",
"it is getting tired",
"it can sense something using the olfactory"
] | D | smell is used for finding food by some animals |
OpenBookQA | OpenBookQA-3866 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
Nectar is used to attract pollinators to what? | [
"flora",
"animals",
"soil",
"hives"
] | A | nectar is used for attracting pollinators by plants |
OpenBookQA | OpenBookQA-3867 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
Rabbits can be found in | [
"filthy magazines",
"nuclear reactors",
"moonbeams",
"treed areas"
] | D | some rabbits live in forests |
OpenBookQA | OpenBookQA-3868 | evolution, biochemistry, plant-physiology, plant-anatomy, life
Title: Plants without bacteria? is it theoretically possible? I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But it is a natural way.
But is it possible to have a world with plants (without mammals or microorganisms and without bacteria) that could exist in the long term. Saying the atmosphere of these world has already enough nitrogen, oxygen and CO2, and of course there is water.
What could break this artificially created world with such conditions (say the world created not from low-level living structures)?
Could bacteria emerge in the world? This is the sort of question that should be considered from more than one perspective. Since this is speculation, take it as a given that there is a lot of 'what if' here.
I doubt most animals and plants can do entirely without bacteria - as you say most of the essential nutrients come from bacteria, who fix nitrogen. If only plants were left on earth, eventually the plants would use up all the nitrogen and they would have to find a way to fix more.
Can bacteria emerge from just a world of plants? I don't think viruses arise spontaneously, but since genomes often have viruses embedded in them, over the course of a billion years or so, its possible since bacteria and viruses continue to be impressed upon our genomes. Would it happen in time? Most would be skeptical whether that timing could work out.
In practice it would be hard to create a world like this. I would be interested to see whether you could sterilize the microorganisms off of seeds without killing the plant for instance. If you're asking about a small sterile environment with only plants, you could do it by adding the nutrients the plants need and giving them sunlight. Such self sustaining systems have been made with cyanobacteria and i'd be surprised if plants could not be included. But these are closed systems and judged by limited amounts of time, so whether this is an answer to your question is not clear. Here it looks like some water plants and fish have been done. If there was a plant that created CO₂ at an adequate rate its possible.
The following is multiple choice question (with options) to answer.
All plants require this | [
"humans",
"insects",
"H2O",
"trees"
] | C | a plants require water for to grow |
OpenBookQA | OpenBookQA-3869 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
deep sea animals live way down in the | [
"volcanoes",
"wet abyss",
"sky",
"mount everest"
] | B | deep sea animals live deep in the ocean |
OpenBookQA | OpenBookQA-3870 | the-sun, photography, solar-eclipse
I can see how the enlarged image of the Sun through a telescope or binoculars might overwhelm the eclipse glasses' filters.
A few observations.
It's really the larger aperture of the instrument that is the problem here. The pupil of your eye is only a few mm in diameter. The objective lens or mirror of a telescope could be anywhere between dozens of mm to hundreds of mm (or thousands for very large instruments). The ratio of areas between telescope aperture and eye pupil is even greater - it's the square of the ratio of diameters.
Let's say your eye's pupil is 2 mm in diameter. Let's say you use a 50 mm aperture telescope (small refractor or binoculars). The diameter ratio is 25x. The area ratio is 625x.
All the light captured by the very large area of the instrument is funneled into your eye through your pupil. With the instrument, now you're getting 625x more energy from the Sun, compared to the naked eye view. It's already dangerous to look at the Sun with the naked eye - with the instrument it's 625x more dangerous. And this is with a very small refractor.
There is a class of "solar filters" that are made to be mounted on the instrument's eyepiece, or after the eyepiece. THESE ARE VERY DANGEROUS! All the increased, focused energy of the Sun is now absorbed by the filter, which can warp, melt, crack, or burst into flames. A filter failure at this point is likely to injure the user. White light filtering for solar observations must always occur ahead of the instrument, not after it.
As for why classic, optical viewfinders were included in that list: it was out of an abundance of caution. Most of those viewfinders do not capture more light than your eye does, but some do. It's better to be safe than sorry. You can't expect everyone to be able to tell whether their viewfinder is dangerous or not. So, in a warning addressed to the general population, just tell them to stay away from it.
Now, if you install a full-aperture solar filter (like the Baader solar film) ahead of the viewfinder, then it's safe to use - provided the filter is attached firmly to the camera and cannot be blown away by some random gust of wind.
The following is multiple choice question (with options) to answer.
looking directly at an eclipse of the Sun causes harm to the | [
"trees",
"clouds",
"rocks",
"organic light receptacle"
] | D | looking directly at an eclipse of the Sun causes harm to the eyes |
OpenBookQA | OpenBookQA-3871 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
Some animals change their appearance completely during a stage of the life cycle known as | [
"metamorphosing",
"metal",
"Seven",
"drawing"
] | A | metamorphosis is a stage in the life cycle process of some animals |
OpenBookQA | OpenBookQA-3872 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
Baby bats start doing what after at least a month after birth? | [
"scavenging",
"teaching class",
"time traveling",
"making magic"
] | A | a bat births live young |
OpenBookQA | OpenBookQA-3873 | electrical-engineering, ethics, sales, safety
But all of those steps are going way above and beyond what you're obligated to do in this particular case. This is especially so when there is a safe usage for the product along with an unsafe approach. And any of those actions are likely to irreparably damage your relationship with that client. Damaging the relationship will impair your credibility with them and make it less likely that they'll listen to your concerns.
So your obligation is to lay it out to them in unambiguous terms that you believe they need to stop using the product in their "preferred" manner and that your firm will no longer provide any support whatsoever regarding future use of that product in that configuration.
The following is multiple choice question (with options) to answer.
which one of these would ensure the least amount of risk to make contact with? | [
"an electric wire wrapped in water",
"an electric wire wrapped in metal",
"an electric wire wrapped in steel",
"an electric wire wrapped in thick cotton"
] | D | electrical insulation requires wrapping a conductor in an insulator |
OpenBookQA | OpenBookQA-3874 | python, parsing, numpy, scipy
if 'electric' in producer.energy:
recipe = self.produce(cls, producer, **kwargs)
recipe.rates['Energy'] = energy
yield recipe
elif 'heat' in producer.energy:
recipe = self.produce(cls, producer, **kwargs)
recipe.rates['Heat'] = energy
yield recipe
elif 'burner' in producer.energy:
for fuel_name in producer.valid_fuel.split('+'):
fuel_name = fuel_name.strip().lower()
fuel = all_items[fuel_name]
fuel_value = parse_power(fuel.fuel_value)
new_kwargs = dict(kwargs)
if self.title:
title = self.title
else:
title = f'{self.resource} ({producer})'
new_kwargs['title'] = f'{title} fueled by {fuel_name}'
recipe = self.produce(cls, producer, **new_kwargs)
recipe.rates[fuel.title] = energy / fuel_value
yield recipe
else:
raise NotImplementedError()
tree_re = re.compile(r'(\d+) .*?\|([^}|]+)\}')
def wood_mining(self) -> Iterable[MiningRecipe]:
miners = tuple(
ManualMiner(tool)
for tool in all_items.values()
if tool.prototype_type == 'mining-tool'
)
for m in self.tree_re.finditer(self.resource.mining_time):
mining_time, source = int(m[1]), m[2]
for miner in miners:
yield self.produce(
MiningRecipe, miner,
mining_hardness=float(self.resource.mining_hardness),
mining_time=mining_time,
title=f'{self.resource} ({miner} from {source})')
The following is multiple choice question (with options) to answer.
a producer is a source of energy for | [
"shoes",
"poetry",
"external food eaters",
"rubber"
] | C | a producer is a source of energy for consumers |
OpenBookQA | OpenBookQA-3875 | meteorology, weather-forecasting, barometric-pressure
Title: Do high pressure systems draw air towards them? I refer to the this very recent article, which quotes Andrew Watkins (Manager of Climate Prediction Services at the Australian Bureau of Meteorology).
My understanding has always been that air flows away from high pressure towards lower pressure, so the following quote from the referenced article confuses me. Can anyone explain it for me?
"There's been a big high pressure system drawing air in off the ocean,
keeping it a bit cooler for Sydney," Dr Watkins said. As Fred said, it's just an unfortunate word choice that makes you think the professor is suggesting air flows towards the high.
Indeed, a surface high pressure south of Sydney would be the circumstance to have the air circulate around it in such a way as to "draw" air onshore from off the shore... even as it's actually really flowing somewhat away from the high.
There's a long-range model forecast showing exactly this setup building after a strong low potentially passes by this week... and so Sydney may be held cooler again just in time for Boxing Day:
from www.pivotalweather.com
(This is only one model's long-range forecast, and the skill in such forecasts is quite low. I present it to show this scenario, not to make any forecast as to whether it'll actually happen next week)
You can see the green arrows are bringing air onshore. This link suggests current ocean surface temperatures are around 23°C (73°F). So that would likely reduce the temperature slightly (if you explore the plots at pivotalweather.com for Australia, it currently shows a forecast high closer to 23°C for the day, rather than nearer the 30s many spots in the area see tomorrow).
The following is multiple choice question (with options) to answer.
If I hear about a warm front I can expect to bring what with me to work? | [
"time traveling",
"candles",
"an umbrella",
"a wagon"
] | C | a warm front causes cloudy and rainy weather |
OpenBookQA | OpenBookQA-3876 | energy, solar-cells
Title: what limitations stop a person from installing solar panels on his/her house? Solar energy is a great form of energy. sourced from the sun, it can save a great deal of electricity bill cost. My question is why doesn't everyone uses it and install panels on their roof.
Of course, sun rays is the most significant factor of all but what other limitations are there to it? Cost of panels, less availability, not efficient, less generation of electricity are few I could think of. But, I'm not sure about any of them.
Since limitations can be many in number and can belong to different nodes of stack exchange network. The question was little related to energy, so I decided to ask it here. If this is not the right platform then do tell. The reason that not everyone has solar panels is that they are not economical.
Simply put, investing X dollars in bonds will usually generate a greater financial return than putting the same X dollars into solar panels. This is because the price of a solar panel is larger than the value of the electricity it will produce during its lifetime.
However, in very sunny climates - and when the government will help pay for the panels - they can be made economical from the point of view of a consumer. Usually, though, governments will subsidize solar panels only to the point where they are almost, but not quite, a good return on investment.
To the extent that solar panels are actually economically efficient utility companies do employ them - and in a much more cost-efficient way than having individual homeowners install and maintain small-scale systems.
The following is multiple choice question (with options) to answer.
To have energy that will last your whole life you'd buy a | [
"car battery",
"loaf of bread",
"turbine",
"tank of gas"
] | C | wind is a renewable resource |
OpenBookQA | OpenBookQA-3877 | geochemistry, chemistry-in-fiction, minerals
They look like extremely poor sources of metals like aluminum, lithium, iron, sodium, calcium, magnesium and potassium.
Now micas. Micas are described by the formula
$\ce{X_2Y_{4–6}Z_8O_{20}(OH,F)_4}$
in which
X is K, Na, or Ca or less commonly Ba, Rb, or Cs;
Y is Al, Mg, or Fe or less commonly Mn, Cr, Ti, Li, etc.;
Z is chiefly Si or Al, but also may include Fe3+ or Ti.
Of interest in this formula are Rb and Cs, no matter how rare, because these are rare by definition. So, adding to the same elements as the above described amphiboles, micas have the advantage of also containing barium, rubidium (!), caesium (!!), manganese, chromium, Titanium and Lithium.
So my question is, what would be a lightly realistic approach to obtain usable compounds from granite? I'm sure real techniques do not exist, but what about science-fictional approaches? Chemists probably have unachievable dreams of tapping this or that potential source for obtaining huge amounts of a substance (until recently, one of those fancy dreams was a way to obtain drinkable water from sea water). I would love to hear any input from this (almost always) lovely community.
The following is multiple choice question (with options) to answer.
What substance found in rocks shares it's name with an object which can take wrinkles from an item worn on the body to cover the skin from the elements? | [
"Iron",
"Stove",
"Copper",
"Steamer"
] | A | rocks sometimes contain iron |
OpenBookQA | OpenBookQA-3878 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
The below surface pebbles of the rio grande are of non rough edges because of? | [
"fish movement",
"rough rocks",
"smoothness",
"fluid moving"
] | D | a canyon is made of rocks |
OpenBookQA | OpenBookQA-3879 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
recycling has a positive impact on the | [
"rocks",
"message boards",
"animes",
"surrounding creature homes"
] | D | recycling has a positive impact on the environment |
OpenBookQA | OpenBookQA-3880 | optics, visible-light, reflection, refraction, lenses
Title: Why can't rainbows form at the start of a storm? I was recently at a park looking at the gorgeous scenery. I looked above and saw thick grey clouds covering up 3/4 of the sky. The sun's light is still visible for 1/4 of the sky, and it looks low enough to refract it's light through the clouds to form a rainbow. The rain started dripping slowly for 10 minutes. At five minutes I decided to take a panorama shot and ask the question, why won't a rainbow form at the start of a storm. I thought the place I was standing had the perfect condition for a rainbow to form.
Here is the panorama scene shot
There were a few rain drops pouring from the sky
The time I looked at the sky was 5:00 p.m., so the sun should be at an appropriate location.
But even if my scenario didn't give a rainbow, is this rare event still possible? The big deal with a rainbow is the angle between the sun and water droplets. The sun has to be behind you and the rainbow will occur at about 42 degrees away from the line from the sun through you. If everything lines up, you can have a rainbow at any time. (I've seen them on water spraying from a hose where things lined up just right.) This will work better when the sun in low in the sky, if the sun is too high in the sky the line from it to you goes into the ground. Since thunderstorms are often afternoon phenomenon, the sun is more likely to be low in the sky after the storm than before.
Looking at your panorama, it doesn't look like the sun was visible to you, so I wouldn't expect to see one.
The following is multiple choice question (with options) to answer.
What do you need to see a rainbow? | [
"water",
"sea monsters",
"bats",
"leprechauns"
] | A | a prism refracts light |
OpenBookQA | OpenBookQA-3881 | evolution, definitions, artificial-selection
It does not lead to new species
In short, 1) it does lead to new species 2) the concept of species is often meaningless as poorly defined 3) evolution > speciation. In more details, below..
It does lead to new species. Different lineages of cabbage are considered different species. Cows and ox are different species. Pigs and boars are often considered different species. While wolves and dogs are considered same species, some lineages within this species (such as a Chihuahua and a Great Dane) are, I think, reproductively isolated. You might also want to have a look at the post Have we ever observed two drosophila lineages that evolved reproductive isolation in labs?
The question of whether selective breeding lead to speciation or not does not matter much on the question of whether it leads to evolution. Speciation is one outcome of evolution but is definitely not the same as evolution. Evolution does not need to lead to speciation. For example, evolution of the lactase gene in humans (see this post) did not lead to any speciation. It is still an evolutionary process.
The concept of species is mainly arbitrary. If you want to understand the concept of species, have a look at the post How could humans have interbred with Neanderthals if we're a different species?.
It decreases, rather than increases, the size of the gene pool (is this actually true?)
The following is multiple choice question (with options) to answer.
if members of a species are born then the species what increases? | [
"water",
"community",
"understanding",
"food"
] | B | if members of a species are born then the population of that species increases |
OpenBookQA | OpenBookQA-3882 | centre-of-gravity
Title: How can I calculate the width of stand required for a Christmas tree based on its height? Given the height and / or weight of a cut tree, what is the best way to calculate the width of stand required to keep it upright?
I have no engineering background, but have been trying to think of a way to work it out. I think the key elements are center of gravity, and I also need to decide what amount of force I am expecting (it will be indoor, so only accidental knocking) to counter.
The tree in question is a 15ft spruce, however if there is a ratio or method I can use to calculate stand width I can do the rest myself. Amazon and some hardware stores sell tree stands rated for the height and weight of the tree.
For example, this is a stand for a 15-foot tall tree from amazon.
Its legs are 30inches long.
'
The following is multiple choice question (with options) to answer.
if a tree stands firm during a windy day, which of these could be holding it in place? | [
"the leaves on the branches",
"the sap in the tree",
"the branches on the stem",
"the roots in the ground"
] | D | roots anchor plants into the soil |
OpenBookQA | OpenBookQA-3883 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
A mammal usually nurses its what? | [
"parents",
"ears",
"head",
"younglings"
] | D | a mammal usually nurses its offspring |
OpenBookQA | OpenBookQA-3884 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
If you were looking for a cold blooded animal a donkey would be | [
"a stuffed animal",
"the wrong animal",
"the right animal",
"a fictional animal"
] | B | a mammal is warm-blooded |
OpenBookQA | OpenBookQA-3885 | everyday-chemistry, water, absorption
Fig. B is complete speculation on my part as I did not return to the home during Winter to observe it. However in Spring when I returned, all of the tubs had experienced a change in their appearance.
All the tubs were now dry again, presumably down to evaporation due to increasing weather temperatures. And therefore releasing all that moisture back into the building again!
Three of the tubs were largely unchanged with some noticable "caking" together of the salt into crumbly, grainy lumps which returned to normal looking salt grains when crushed.
The most profound change from the remaining tubs was as you see in Fig. C of the diagram.
The salt had actually accumulated on the walls of the tub as a fine sediment. This suggests that water had accumulated in large amounts in the tub and had in fact risen higher than the original depth of the dry salt grains! I'd estimate that the tub would have had to accumulate about 0.5kg of water in order for the water/salt solution to reach the depth indicated by the dry sediment.
The salt had solidified into a single, large mass. The volume seemed to have increased noticeably but the density had also decreased accordingly, so the salt had basically expanded in it's container and solidified. It was crumbly and brittle and some of it had been reduced to a very fine sediment.
The home is a single storey, about 12m x 4.5m x 2.5m in volume.
My questions then:
Is this a valid technique for capturing excess moisture over Winter?
Are my observations and presumptions reasonable... Is Fig. B what really happened?
What is the chemistry / physics process that caused the salt to be transformed from Fig. A to Fig. C?
How many times did the tubs cycle between states B and C? Was it a single cycle that lasted all of winter, or a daily cycle following ambient weather temperatures? I could not tell just by looking at C on the last day of the experiment. According to Transportation Information Service: Salt:
The following is multiple choice question (with options) to answer.
Salt was at one time | [
"currency",
"unrealistic",
"imaginary",
"a feeling"
] | A | adding salt to a solid decreases the freezing point of that solid |
OpenBookQA | OpenBookQA-3886 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
As wolves need more energy to catch fast prey | [
"their pulse will decrease",
"their shoes will wear out",
"their heart rates will go higher",
"they will start using vehicles to chase their prey"
] | C | as energy required for an activity increases , pulse will increase |
OpenBookQA | OpenBookQA-3887 | civil-engineering, building-design
Title: Is it OK for a 2 story house not have a column or pillar sorry for my english. I was looking to buy a house. I saw some in my hometown, which is very affordable.
but on a picture of the house they are selling I found on the net troubled me.
no pillar/column, just hollowblocks and some steel bars.
kindly look at the pic.
I found it in this site
https://fiestacommunitiesblog.wordpress.com/tag/fiesta-communities/ As @SamFarjamirad states it's best to consult a knowledgeable construction engineer where you live, or in your region, because such people would know the building codes & construction practices for your region. A column or pillar for a two storey house may not be necessary if the load bearing walls are designed & built properly. This may include internal load bearing wall, inside the house. The other thing to be wary of is the quality of the foundations for the load bearing walls. Also, if the house to be renovated later all load bearing walls must not be removed or altered.
It looks like the steel is being threaded through the hollow block in the external walls. This would be done to increase the flexibility of the house during earthquakes and should a typhoon/cyclone/hurricane affect the house. Internal load bearing walls should also have such steel reinforcement.
If designed and built correctly such steel reinforced walls should not collapse. They might crack during extreme natural events but they should not fall and collapse the house.
Looking at the picture you included, some things that I found strange were:
The following is multiple choice question (with options) to answer.
A place without a sand bar is indicative of which of these characteristics? | [
"a flow of sedimentation to settle",
"a stacking of silty sediments",
"a downstream movement without sediments",
"a rapid movement of sediments for downward deposit"
] | C | a sandbar is formed by water moving sediment downstream |
OpenBookQA | OpenBookQA-3888 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
A consumer is unable to produce its own what? | [
"offspring",
"children",
"emotions",
"sustenance"
] | D | a consumer can not produce its own food |
OpenBookQA | OpenBookQA-3889 | newtonian-mechanics
I should add that the above is simply what I, as a physicist with a fairly long experience, suspect is what is going on. It is not something I have read about and I am sure there is somewhere a more thorough discussion. So I hope I am right; I think I have a good argument. As I have described it above, I have in mind mainly the last part of the process where the wood only moves a little relative to the metal. In the earlier part, when the wood moves through a larger distance, it is inertia that is the main consideration, just like in the party trick where you abruptly whisk away a table cloth and the dishes on the table stay where there are. The more abrupt the better.
Added remark
It occurred to me that there is another thing worth mentioning here, that makes this method preferable to resting the axe head on something, or supporting the handle on a work top and hitting the head. It is that by hitting the end of the handle, with the head just hanging, you are going to deliver the force more accurately at the join, because it travels along the handle in exactly the direction you want. If instead you strike the head then there is a danger it will be knocked slightly obliquely, introducing a random tilt with each blow, which is liable to deform the wood and thus loosen the fit.
The following is multiple choice question (with options) to answer.
What is most impervious to an ax? | [
"a thin branch",
"a neck",
"a twig",
"a boulder"
] | D | as the thickness of an object increases , the resistance to damage of that object will increase |
OpenBookQA | OpenBookQA-3890 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
If an animals starts eating fewer calories than its used to, its body will eventually | [
"float",
"fly",
"shrink",
"get bigger"
] | C | as the amount of food an animal eats decreases , that organism will become thinner |
OpenBookQA | OpenBookQA-3891 | geophysics, plate-tectonics
Title: Equatorial bulge and tectonic plates It is well known that the Earth is not a sphere, but rather it bulges at the equator. Also it is well known that the Earth's crust is composed of 7 or 8 (depending on definition) major tectonic plates, which are able to move on top of the asthenosphere, the upper layer of the Earth's mantle.
Due to the equatorial bulge, it would seem as though plates near the equator should not be able to drift away from the equator, and plates away from the equator should not be able to drift near the equator, since they will not be of the right shape to fit over these portions of the Earth. So how are the plates able to drift to and from the equator when the surface of the Earth is shaped differently there? The plates are not as rigid as you think. You seem to be imagining the situation as something like this: I boil an egg and take the shell off in pieces, but I can't take a piece of shell from the end and make it lay flat on the side of the egg. However, rock is not that rigid on scales of thousands of kilometres and millions of years (I don't think there exists any material which would be that rigid). Also, Earth's equatorial bulge is tiny relative to its diameter -- less than 50km. Tectonic plates move very slowly, and there is plenty of time for them to deform as they move.
The following is multiple choice question (with options) to answer.
Tectonic plates are like a large | [
"pizza",
"jenga",
"marshmallow",
"candy cane"
] | B | a tectonic plate moves along a fault line |
OpenBookQA | OpenBookQA-3892 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
If a thing is residing in a hollowed out part of a tree, then it is probably | [
"a whale",
"an antelope",
"a person",
"a scavenger"
] | D | some raccoons live in hollow logs |
OpenBookQA | OpenBookQA-3893 | herpetology, poison
Title: Poisonous Snakes consuming poison (chemical) While travelling with my Son to a religious shrine, we saw a dead snake lying on the road.
My Son asked a curious question to me "Dad, if Poisonous snakes consume poison (Chemical), Will they die"?
I feel the answer is depends upon the type of poisonous snake viz Cobra, Python etc and how much the reptile has consumed the poison. i.e. quantity.
What is the correct answer? If any living thing consumes enough of a poison it will die. But I feel that is not what you want to ask.
Perhaps you meant to ask if a snake will die if it drinks its own venom? That would make more sense as a question.
In English, venom and poison mean different things when talking about a toxic chemical produced by an animal.
Poison is a toxic chemical produced by an animal that is meant to be ingested/eat/drink.
Venom is a toxic chemical produced by an animal that is meant to be injected into the bloodstream.
So a snake bite has venom, but a colourful tree frog has poison on its skin.
Venom is typically not nearly as harmful if ingested, even if by a different animal, because it is meant to act directly in the bloodstream
The following is multiple choice question (with options) to answer.
Poison causes harm to | [
"car engines",
"televisions",
"wombats",
"corpses"
] | C | poison causes harm to living things |
OpenBookQA | OpenBookQA-3894 | species-identification, ornithology
Title: Help me find out what this bird is (description, no picture) A while ago I read about this bird(s) whose species status was not confirmed. This was because they had a very large distribution and birds in adjacent population could breed with each other but birds at each end of the distribution (western Europe and South Asia I think) couldn't. I am pretty sure that they were some kind of gull and from Europe to Asia their wings got lighter, from black to grey. I think I might have read about them in a Richard Dawkins book.
Does anyone know the species I'm talking about? You're describing a Ring Species: "a connected series of neighbouring populations, each of which can interbreed with closely sited related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population".
The classic ring species is the Herring Gull complex, and that's probably what you read about:
The classical example of the ring species model was originally based upon the herring gull complex (Mayr 1942). This group comprises more than 20 taxa of large gulls (Haffer 1982) which together occupy a circumpolar breeding range in the northern hemisphere. ... Mayr envisioned all taxa of the circumpolar chain to be connected by gene flow, while herring and lesser black-backed gulls in Europe, the hypothetical endpoints of the ring, have reached full reproductive isolation and now coexist as distinct species.
--The Herring Gull Complex (Larus argentatus - fuscus - cachinnans) as a Model Group for Recent Holarctic Vertebrate Radiations
However, recent genetic work shows that the situation is even more complicated than this, and it's questionable whether they really are "ring species":
Contrary to the ring-species model, we find no genetic evidence for a closure of the circumpolar ring through colonization of Europe by North American herring gulls. However, closure of the ring in the opposite direction may be imminent, with lesser black-backed gulls about to colonize North America.
--The herring gull complex is not a ring species.
The following is multiple choice question (with options) to answer.
A gull will build a nest because | [
"it saw other gulls doing the same",
"of something in its genes",
"it wants to tidy up the area",
"it's mother taught it to do that"
] | B | An example of an inherited behavior is a bird building a nest |
OpenBookQA | OpenBookQA-3895 | electromagnetism, magnetic-fields, everyday-life
Title: How is magnetism ''conducted'' through a non-magnetic metal? I have a ball of metal about an inch in diameter and a concave disc of another metal (which is magnetic) around the ring of the disc (about $12 {\rm mm}$ in diameter). I don't know which metals they are. The ball is not magnetic on its own. That is paramagnetism, right?
The magnetic ring is strongly attracted to the surface of the ball, 'sticking' to it. However, I can stick a paperclip on the opposite side of the ball as if it has become magnetic itself, until I remove the magnetic ring from the ball.
When I wave the paperclip the same distance from only the ring itself, I feel no force at that distance.
Has the strong magnetic field of the ring caused a temporary magnetic alignment through the metal of the ball, allowing the paperclip to be attracted to it while the ring remains? The phenomenon you describe is ferromagnetism not paramagnetism.
Ferromagnetic materials like iron behave as if they contain many tiny bar magnets (called magnetic domains if you're interested to pursue this further), but because the magnet domains are aligned randomly the fields cancel out and there is no net magnetic field.
However if you put a ferromagnetic material in a magnetic field the external field will cause partial alignment of the magnetic domains. This induces a magnetic field in the originally unmagnetised iron, and that's why your paper clip sticks to the ball. However if you remove the external magnetic field the domains will go back to their original alignment, the net magnetic field will go back to zero and the paper clip will fall off again.
If you apply a very strong field and/or combine it with heating and cooling you can permanently change the alignment of the magnetic domains so they remain aligned when the external field is removed. This is how you make permanent magnets.
The following is multiple choice question (with options) to answer.
a paper clip is often made of ferromagnetic | [
"hard shiny material",
"cake",
"water",
"rubber"
] | A | a paper clip is often made of ferromagnetic metals |
OpenBookQA | OpenBookQA-3896 | thermodynamics, energy
$\frac{\text{d}Q}{\text{d}t}$ is the heat flux. Quite literally it's the power (energy per unit of time) needed to maintain the house at a constant inside temperature of $T_i$. Note that here it is negative because it represents a loss of heat (energy).
$u$ is the overall heat transfer coefficient. The lower it is, the better. Low values are obtained with good double (or triple) glazing, cavity insulation, insulating wall paper, loft insulation, etc.
$T_i$ and $T_o$ are the inside and outside temperatures respectively. Clearly high $T_i$ and/or low $T_o$ increases heat loss.
$A$ is the total surface area of the house exposed, to the elements.
The heat required to bring a house back to the target temperature $T_i$ from a hibernation temperature $T_h$ ($<T_i$) can also be modeled:
$$\Delta Q=mC(T_h-T_i)$$
where:
$\Delta Q$ is the amount of heat energy needed.
$m$ is the total mass of the house.
$C$ is the specific heat energy of the house.
At the start of your absence, the inside of house is broadly at 21°C.
If you turn the thermostat to 15°C upon leaving, there will be no gas
spent during the time house cools down. Then the gas spent to maintain
15°C will be about the same amount as to maintain 21°C. Then when you
return, you have to heat the house up and you expend the energy you
saved during cooling, to heat the house back up.
Here, for an amount of time $\Delta t$, we can compare two quantities:
$$\Delta Q_1=-uA(T_i-T_o)\Delta t$$
and with 'hibernation':
$$\Delta Q_2=-uA(T_h-T_o)\Delta t+mC(T_h-T_i)$$
Whichever of the two quantities is the least negative is the most cost-effective strategy.
The following is multiple choice question (with options) to answer.
One way to retain your own thermal energy is to | [
"sit in snow",
"wear fluffy socks",
"sleep in freezers",
"bathe in ice"
] | B | a thermal insulator slows the transfer of heat |
OpenBookQA | OpenBookQA-3897 | Hey, thanks for your help guys. For a minute there, I thought that this theoretical person could not safely expect to live to be 82 years old.
9. Jun 16, 2012
### SW VandeCarr
In fact, on a purely probabilistic basis, for any finite time no matter how large, there is a non zero probability that a person would survive that long. So for a sufficiently large population, there would be a theoretic person that would live 100,000 years. This, of course, has no basis in biology.
In terms of the probability of being murdered, the model would not hold for the 100,000 year old person. In terms of the model, probably the best one can do is assume the proportion of causes of death would be constant. The calculation above needs to be corrected for overall survival in terms of death from any cause.
Last edited: Jun 16, 2012
10. Jun 16, 2012
### viraltux
Interesting... but 0.37% is not that small percentage, don't you think? That means, roughly speaking, that a community of around 300 persons can expect that one of them will be murdered.
If you consider that the number of people we know plus acquaintances can easily be around 300 persons that would mean that most 82 year old persons know of someone in their circles who has been murdered. Mmm... that might be an interesting survey.
11. Jun 16, 2012
### SW VandeCarr
As I said in my previous post, this is a misapplication of statistics. You have to consider survival in terms of all cause death. If you just consider the murder rate, then at some point nearly everyone gets murdered.
12. Jun 16, 2012
### moonman239
I know that.
This person will not die until he reaches age 82, if he is not murdered. As mentioned before, this person has a 68% chance of living to be 82.
13. Jun 16, 2012
### D H
Staff Emeritus
The probability of living to 82 per this problem is 99.63%, not 68%. You missed the decimal point on the 0.37%.
14. Jun 16, 2012
### SW VandeCarr
The following is multiple choice question (with options) to answer.
A decomposer might thrive more on | [
"Magic",
"Jupiter",
"Time Traveling",
"Old turkey"
] | D | dead organisms are the source of nutrients for decomposers |
OpenBookQA | OpenBookQA-3898 | # Which payoff do you want to go for?
Payoff 1.
Toss 5 coins. You get $1 for each consecutive HT that you get. Payoff 2. Toss 5 coins. You get$1 for each consecutive HH that you get.
For example, if you tossed HTHHH, under payoff 1 you will get $1, but under payoff 2 you will get$2.
Note by Calvin Lin
3 years, 2 months ago
MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold
- bulleted- list
• bulleted
• list
1. numbered2. list
1. numbered
2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1paragraph 2
paragraph 1
paragraph 2
[example link](https://brilliant.org)example link
> This is a quote
This is a quote
# I indented these lines
# 4 spaces, and now they show
# up as a code block.
print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.
print "hello world"
MathAppears as
Remember to wrap math in $$...$$ or $...$ to ensure proper formatting.
2 \times 3 $$2 \times 3$$
2^{34} $$2^{34}$$
a_{i-1} $$a_{i-1}$$
\frac{2}{3} $$\frac{2}{3}$$
\sqrt{2} $$\sqrt{2}$$
\sum_{i=1}^3 $$\sum_{i=1}^3$$
\sin \theta $$\sin \theta$$
\boxed{123} $$\boxed{123}$$
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The following is multiple choice question (with options) to answer.
After a whiteout you need to | [
"remove snow",
"login to Warcraft",
"wish for snow",
"apply suntan lotion"
] | A | snowy means a large amount of snow |
OpenBookQA | OpenBookQA-3899 | telescope, mars
Have a look at this guide explaining how consumer-grade computer webcams can be used. It contains a neat comparison of a single frame and a stacked image.
Please note that I'm merely speculating as to which techiniques could be used to obtain such images. I can see that the author posted their email on the S&T site and that there's a comments section as well. Feel free to ask them yourself.
The following is multiple choice question (with options) to answer.
Which would you use to record a live basketball game | [
"a camera bag",
"a GoPro",
"a Nikon lens",
"a camera flash"
] | B | a camera is used for recording images |
OpenBookQA | OpenBookQA-3900 | glaciology, glacier, ice
What would be a good average to take? This is a non-trivial issue. When you look at volume change of a glacier, you typically subtract two digital elevation models to obtain the difference between the two. First, you must differentiate between ice sheets where ice berg calving reduces volume and more ordinary glaciers with melt processes. There are of course calving glaciers as well so it is possible to get into great detail for any one specific glacier, so here I will just discuss the most common case which is a smaller glacier with melt-freeze conditions.
The change in elevation differs in magnitude across the glacier surface due to the movement of the glacier and accumulation-melt processes. The surface material can be (1) glacier ice, (2) snow, (3) firn snow that has survived a melt season) or (4) super imposed ice all with more or less differing densities, you need to assess what sort of material has been removed.
Ice can be approximated by a density of 900 kg/m3, firn has a density of about 600 kg/m3 but it must be remembered that the firn is converted to glacier ice by metamorphic processes so that the density changes with depth from 600 to 900 kg/m3. the transition to ice occurs at depths of about 30 m in temperate glaciers although few studies exist on the actual processes that occur. Snow have very differing densities but considering averages, I would say that it would vary between 350 to maybe 500 kg/m3 for winter (cold) conditions and around 550 kg/m3 for a melting snow pack. Super-imposed ice is closer to ice and probably varies in the upper range of 800--900 kg/m3.
To make matters worse, snow superimposes firn which in turn superimposes ice. This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.
So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.
The following is multiple choice question (with options) to answer.
A heavy glacier moving across a continent affects what's underneath it by | [
"compaction",
"salt tectonics",
"arctic foxes",
"exfoliation"
] | A | sedimentary rocks are formed from sediment compacting together |
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