instruction stringlengths 5 342 | input stringlengths 18 558 | output stringclasses 7
values | context stringlengths 31 6.57k |
|---|---|---|---|
a magnets force is | (A) a force of repulsion only (B) a force of attraction only (C) exerted over a distance (D) two of the above | C | The force that a magnet exerts on certain materials is called magnetic force. Like electric force, magnetic force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other. |
when two magnets are brought close together, their magnetic fields interact. | (A) true (B) false | A | Like the electric field that surrounds a charged particle, a magnetic field surrounds a magnet. This is the area around the magnet where it exerts magnetic force. Figure 24.3 shows the magnetic field surrounding a bar magnet. Tiny bits of iron, called iron filings, were placed under a sheet of glass. When the magnet wa... |
lines of force around two magnetic poles push apart when | (A) both poles are north poles (B) both poles are south poles (C) one pole is a north pole and one pole is a south pole (D) two of the above | D | When charged particles are close enough to exert force on each other, their electric fields interact. This is illustrated in the Figure 1.2. The lines of force bend together when particles with different charges attract each other. The lines bend apart when particles with like charges repel each other. Q: What would th... |
ways that machines may make work easier include changing the | (A) amount of force applied (B) distance over which force is applied (C) direction in which force is applied (D) any of the above | D | Contrary to popular belief, machines do not increase the amount of work that is done. They just change how the work is done. Machines make work easier by increasing the amount of force that is applied, increasing the distance over which the force is applied, or changing the direction in which the force is applied. Q: I... |
the equation for calculating actual mechanical advantage is | (A) Actual Mechanical Advantage = Input Force/Output Force (B) Actual Mechanical Advantage = Input Distance/Output Distance (C) Actual Mechanical Advantage = Output Force/Input Force (D) Actual Mechanical Advantage = Output Distance/Input Distance | C | How much a machine changes the input force is its mechanical advantage. Mechanical advantage is the ratio of the output force to the input force, so it can be represented by the equation: Actual Mechanical Advantage = Output force Input force Note that this equation represents the actual mechanical advantage of a machi... |
the equation for calculating ideal mechanical advantage is | (A) Ideal Mechanical Advantage = Input Force/Output Force (B) Ideal Mechanical Advantage = Input Distance/Output Distance (C) Ideal Mechanical Advantage = Output Force/Input Force (D) Ideal Mechanical Advantage = Output Distance/Input Distance | B | It can be difficult to measure the input and output forces needed to calculate actual mechanical advantage. Its usually much easier to measure the input and output distances. These measurements can then be used to calculate the ideal mechanical advantage. The ideal mechanical advantage represents the multiplication of ... |
the mechanical advantage of a machine may be less than, equal to, or greater than 1. | (A) true (B) false | A | As you read above, some machines increase the force put into the machine, while other machines increase the distance over which the force is applied. Still other machines change only the direction of the force. Which way a machine works affects its mechanical advantage. For machines that increase force including ramps,... |
types of mechanical waves include | (A) transverse waves (B) longitudinal waves (C) surface waves (D) all of the above | D | There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. |
mechanical waves can travel through liquids and gases but not through solids. | (A) true (B) false | B | The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the... |
particles of the medium actually travel along with a mechanical wave. | (A) true (B) false | B | The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the... |
in which type of wave do particles of the medium move in small circles? | (A) surface wave (B) transverse wave (C) longitudinal wave (D) none of the above | A | The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the... |
a longitudinal wave is a combination of a transverse wave and a surface wave. | (A) true (B) false | B | A surface wave is a combination of a transverse wave and a longitudinal wave. A transverse wave is a wave in which particles of the medium move up and down perpendicular to the direction of the wave. A longitudinal wave is a wave in which particles of the medium move parallel to the direction of the wave. In a surface ... |
atomic mass is an atoms number of | (A) protons (B) neutrons (C) protons plus electrons (D) protons plus neutrons | B | Electrons have almost no mass. Instead, almost all the mass of an atom is in its protons and neutrons in the nucleus. The nucleus is very small, but it is densely packed with matter. The SI unit for the mass of an atom is the atomic mass unit (amu). One atomic mass unit equals the mass of a proton, which is about 1.7 ... |
elements in a given period of mendeleevs table have similar properties. | (A) true (B) false | B | You can see how Mendeleev organized the elements in Figure 6.2. From left to right across each row, elements are arranged by increasing atomic mass. Mendeleev discovered that if he placed eight elements in each row and then continued on to the next row, the columns of the table would contain elements with similar prope... |
in mendeleevs table, how many elements are there in each period? | (A) 4 (B) 8 (C) 12 (D) 18 | B | Rows of the modern table are called periods, as they are in Mendeleevs table. From left to right across a period, each element has one more proton than the element before it. In each period, elements change from metals on the left side of the table, to metalloids, and then to nonmetals on the right. Figure 6.4 shows th... |
only some of the unknown elements that mendeleev predicted were ever discovered. | (A) true (B) false | B | Did you notice the blanks in Mendeleevs table? They are spaces that Mendeleev left blank for elements that had not yet been discovered when he created his table. He predicted that these missing elements would eventually be discovered. Based on their position in the table, he even predicted their properties. For example... |
the lattice-like structure of a metal consists of negative metal ions in a sea of electrons. | (A) true (B) false | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
properties of metals that are possible because of their freely moving electrons include the ability to | (A) conduct electricity (B) bend without breaking (C) form hydrogen bonds (D) two of the above | D | The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into t... |
a metallic bond forms when one metal atom shares a pair of electrons with another metal atom. | (A) true (B) false | B | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
metallic bonds form only between atoms of two or more different metals. | (A) true (B) false | B | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
in the lattice-like structure of a metal | (A) metal ions can move freely (B) valence electrons are in fixed positions (C) pairs of ions and electrons can move freely (D) none of the above | D | The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into t... |
which of the following elements form(s) metallic bonds? | (A) iron (B) oxygen (C) carbon (D) two of the above | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
which of the following elements is not a metalloid? | (A) arsenic (B) boron (C) carbon (D) gemanium | C | Groups 13-16 each contain one or more metalloids. These groups are shown in Figure 6.12. Group 13 is called the boron group. The only metalloid in this group is boron (B). The other four elements are metals. All group 13 elements have three valence electrons and are fairly reactive. All are solids at room temperature. ... |
the metalloid class is the smallest class of elements. | (A) true (B) false | A | Metalloids are the smallest class of elements. (The other two classes of elements are metals and nonmetals). There are just six metalloids. In addition to silicon, they include boron, germanium, arsenic, antimony, and tellurium. Metalloids fall between metals and nonmetals in the periodic table. They also fall between ... |
how many valence electrons do metalloids have? | (A) 1–2 (B) 2–4 (C) 3–6 (D) 6–8 | C | How metalloids behave in chemical interactions with other elements depends mainly on the number of electrons in the outer energy level of their atoms. Metalloids have from three to six electrons in their outer energy level. Boron, pictured in the Figure 1.1, is the only metalloid with just three electrons in its outer ... |
metalloids are generally | (A) dull (B) brittle (C) ductile (D) malleable | B | Most metalloids have some physical properties of metals and some physical properties of nonmetals. For example, metals are good conductors of both heat and electricity, whereas nonmetals generally cannot conduct heat or electricity. And metalloids? They fall between metals and nonmetals in their ability to conduct heat... |
some metalloids are liquids at room temperature. | (A) true (B) false | B | Most metalloids have some physical properties of metals and some physical properties of nonmetals. For example, metals are good conductors of both heat and electricity, whereas nonmetals generally cannot conduct heat or electricity. And metalloids? They fall between metals and nonmetals in their ability to conduct heat... |
metalloids fall between metals and nonmetals in the periodic table. | (A) true (B) false | A | Groups 13-16 of the periodic table (orange in the Figure 1.1) are the only groups that contain elements classified as metalloids. Unlike other groups of the periodic table, which contain elements in just one class, groups 13-16 contain elements in at least two different classes. In addition to metalloids, they also con... |
metals are the largest of the three classes of elements. | (A) true (B) false | A | Metals are elements that can conduct electricity. They are one of three classes of elements (the other two classes are nonmetals and metalloids). Metals are by far the largest of the three classes. In fact, most elements are metals. All of the elements on the left side and in the middle of the periodic table, except fo... |
properties of most metals include | (A) high melting point (B) ability to conduct heat (C) shiny appearance (D) all of the above | D | Elements in the same class share certain basic similarities. In addition to conducting electricity, many metals have several other shared properties, including those listed below. Metals have relatively high melting points. This explains why all metals except for mercury are solids at room temperature. Most metals are ... |
some metals are gases at room temperature. | (A) true (B) false | B | As their name suggests, nonmetals generally have properties that are very different from the properties of metals. Properties of nonmetals include a relatively low boiling point, which explains why many of them are gases at room temperature. However, some nonmetals are solids at room temperature, including the three pi... |
the properties of metals depend mainly on their number and arrangement of neutrons. | (A) true (B) false | B | Metalloids are the smallest class of elements. (The other two classes of elements are metals and nonmetals). There are just six metalloids. In addition to silicon, they include boron, germanium, arsenic, antimony, and tellurium. Metalloids fall between metals and nonmetals in the periodic table. They also fall between ... |
electromagnetic waves vary in their | (A) speed (B) frequency (C) wavelength (D) two of the above | D | Although all electromagnetic waves travel at the same speed, they may differ in their wavelength and frequency. |
the electromagnetic spectrum is defined as the full range of colors of visible light. | (A) true (B) false | B | Visible light is the part of the electromagnetic spectrum (Figure 23.3) that humans can see. Visible light includes all the colors of the rainbow. Each color is determined by its wavelength. Visible light ranges from violet wavelengths of 400 nanometers (nm) through red at 700 nm. There are parts of the electromagnetic... |
microwaves have lower frequencies than other radio waves. | (A) true (B) false | B | The shortest wavelength, highest frequency radio waves are called microwaves (see Figure 21.7). Microwaves have more energy than other radio waves. Thats why they are useful for heating food in microwave ovens. Microwaves have other important uses as well, including cell phone transmissions and radar, which is a device... |
microwaves are used for | (A) heating food (B) cell phone transmissions (C) radar (D) all of the above | D | Find the microwave in the Figure 1.1. A microwave is an electromagnetic wave with a relatively long wavelength and low frequency. Microwaves are often classified as radio waves, but they have higher frequencies than other radio waves. With higher frequencies, they also have more energy. Thats why microwaves are useful ... |
microwave signals can be interrupted by buildings and other obstructions. | (A) true (B) false | A | Cell phone signals are carried through the air as microwaves. You can see how this works in the Figure 1.2. A cell phone encodes the sounds of the callers voice in microwaves by changing the frequency of the waves. This is called frequency modulation. The encoded microwaves are then sent from the phone through the air ... |
radar is used for | (A) computing the speed of vehicles (B) detecting air traffic (C) tracking storms (D) all of the above | D | Radar stands for Radio Detection and Ranging (Figure 1.2). A transmitter sends out radio waves that bounce off the nearest object and then return to a receiver. Weather radar can sense many characteristics of precipitation: its location, motion, intensity, and the likelihood of future precipitation. Doppler radar can a... |
the shape of a mirrors surface determines the type of image that it forms. | (A) true (B) false | A | Mirrors are usually made of glass with a shiny metal backing that reflects all the light that strikes it. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the type of image the mirror forms. For example, the image may be real or virtual. A real image forms in front of a mirror where r... |
a real image | (A) forms in front of a mirror (B) forms where rays of light actually meet (C) is always smaller than the reflected object (D) two of the above | D | A mirror is typically made of glass with a shiny metal backing that reflects all the light that strikes it. When a mirror reflects light, it forms an image. An image is a copy of an object that is formed by reflection or refraction. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the... |
a virtual image | (A) appears to be behind the mirror (B) doesn’t really exist (C) is always larger than the reflected object (D) two of the above | D | A mirror is typically made of glass with a shiny metal backing that reflects all the light that strikes it. When a mirror reflects light, it forms an image. An image is a copy of an object that is formed by reflection or refraction. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the... |
the type of mirror in question 6 always forms real images. | (A) true (B) false | B | Mirrors are usually made of glass with a shiny metal backing that reflects all the light that strikes it. Mirrors may have flat or curved surfaces. The shape of a mirrors surface determines the type of image the mirror forms. For example, the image may be real or virtual. A real image forms in front of a mirror where r... |
the type of mirror in question 8 always forms life-sized images. | (A) true (B) false | B | The mirror in the opening photo is a plane mirror. This is the most common type of mirror. It has a flat reflective surface and forms only virtual images. The image formed by a plane mirror is also right-side up and life sized. But something is different about the image compared with the real object in front of the mir... |
which statement about convex mirrors is true? | (A) They curve outward like the outside of a bowl (B) They form only real images (C) They form only enlarged images (D) two of the above | A | The other type of curved mirror, a convex mirror, is shaped like the outside of a bowl. This type of mirror forms only virtual images. The image is always right-side up and smaller than the actual object, which makes the object appear farther away than it really is. You can see how a convex mirror forms an image in Fig... |
the modern periodic table is based on mendeleevs earlier periodic table. | (A) true (B) false | A | A periodic table is still used today to organize the elements. You can see a simple version of the modern periodic table in the Figure 1.1. The modern table is based on Mendeleevs table, except the modern table arranges the elements by increasing atomic number instead of atomic mass. Atomic number is the number of prot... |
each element has a unique atomic number. | (A) true (B) false | A | The number of protons per atom is always the same for a given element. However, the number of neutrons may vary, and the number of electrons can change. |
how many groups are there in the modern periodic table? | (A) 7 (B) 8 (C) 12 (D) 18 | B | Columns of the modern table are called groups, as they are in Mendeleevs table. However, the modern table has many more groups18 compared with just 8 in Mendeleevs table. Elements in the same group have similar properties. For example, all elements in group 18 are colorless, odorless gases, such as neon (Ne). (Neon is ... |
all the periods of the modern periodic table contain the same number of elements. | (A) true (B) false | B | Rows of the modern table are called periods, as they are in Mendeleevs table. From left to right across a period, each element has one more proton than the element before it. In each period, elements change from metals on the left side of the table, to metalloids, and then to nonmetals on the right. Figure 6.4 shows th... |
the number of each period in the modern periodic table represents the number of | (A) energy levels containing electrons (B) electrons in each energy level (C) protons plus neutrons in the nucleus (D) none of the above | A | Rows of the modern periodic table are called periods, as they are in Mendeleevs table. From left to right across a period, each element has one more proton than the element before it. Some periods in the modern periodic table are longer than others. For example, period 1 contains only two elements: hydrogen (H) and hel... |
in covalent compounds, elements are held together by the force of attraction between oppositely charged atoms. | (A) true (B) false | B | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
covalent compounds form structures called crystals. | (A) true (B) false | B | Many compounds form molecules, but ionic compounds form crystals instead. A crystal consists of many alternating positive and negative ions bonded together in a matrix. Look at the crystal of sodium chloride (NaCl) in the Figure bonds. Sodium chloride crystals are cubic in shape. Other ionic compounds may have crystals... |
prefixes may be used in the name of a molecular compound to represent the numbers of each atom in a molecule of the compound. which prefix represents five atoms? | (A) tetra- (B) tri- (C) hexa- (D) penta- | C | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
which of the following is a correct rule for naming molecular compounds? | (A) The name of the element closer to the left side of the periodic table comes first (B) The name of the element closer to the right side of the periodic table comes first (C) The name of the element closer to the bottom of the periodic table comes first (D) The name of the element closer to the top of the periodic ta... | A | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
which of the following is a property of most molecular compounds? | (A) ability to dissolve in water (B) ability to burn easily (C) ability to conduct electricity (D) very high boiling point | B | Covalent compounds have different properties than ionic compounds because of their bonds. Covalent compounds exist as individual molecules rather than crystals. It takes less energy for individual molecules than ions in a crystal to pull apart. As a result, covalent compounds have lower melting and boiling points than ... |
factors that determine an objects momentum include its | (A) mass (B) velocity (C) acceleration (D) two of the above | D | What if a friend asked you to play catch with a bowling ball, like the one pictured in Figure 14.10? Hopefully, you would refuse to play! A bowling ball would be too heavy to catch without risk of injury assuming you could even throw it. Thats because a bowling ball has a lot of mass. This gives it a great deal of mome... |
all objects with mass have momentum. | (A) true (B) false | B | What if a friend asked you to play catch with a bowling ball, like the one pictured in Figure 14.10? Hopefully, you would refuse to play! A bowling ball would be too heavy to catch without risk of injury assuming you could even throw it. Thats because a bowling ball has a lot of mass. This gives it a great deal of mome... |
to calculate an objects momentum, you would use the formula | (A) momentum = mass x acceleration (B) momentum = mass x velocity (C) momentum = mass/acceleration (D) momentum = mass/velocity | B | Momentum can be calculated by multiplying an objects mass in kilograms (kg) by its velocity in meters per second (m/s). For example, assume that a golf ball has a mass of 0.05 kg. If the ball is traveling at a velocity of 50 m/s, its momentum is: Momentum = 0.05 kg 50 m/s = 2.5 kg m/s Note that the SI unit for moment... |
which football player has greater momentum? | (A) Ted: mass = 60 kg (B) velocity = 20 m/s (C) b Todd: mass = 80 kg (D) velocity = 17 m/s (E) c Tom: mass = 90 kg (F) velocity = 15 m/s (G) d Tim: mass = 100 kg (H) velocity = 12 m/s | B | Momentum can be calculated by multiplying an objects mass in kilograms (kg) by its velocity in meters per second (m/s). For example, assume that a golf ball has a mass of 0.05 kg. If the ball is traveling at a velocity of 50 m/s, its momentum is: Momentum = 0.05 kg 50 m/s = 2.5 kg m/s Note that the SI unit for moment... |
which football players in question 7 have the same momentum? | (A) Ted and Todd (B) Todd and Tom (C) Ted and Tim (D) none of the above | C | Momentum can be calculated by multiplying an objects mass in kilograms (kg) by its velocity in meters per second (m/s). For example, assume that a golf ball has a mass of 0.05 kg. If the ball is traveling at a velocity of 50 m/s, its momentum is: Momentum = 0.05 kg 50 m/s = 2.5 kg m/s Note that the SI unit for moment... |
the faster an object is moving, the harder it is to stop. | (A) true (B) false | A | When skater 2 runs into skater 1, hes going faster than skater 1 so he has more momentum. Momentum is a property of a moving object that makes it hard to stop. Its a product of the objects mass and velocity. At the moment of the collision, skater 2 transfers some of his momentum to skater 1, who shoots forward when ska... |
aspects of motion include speed and direction. | (A) true (B) false | A | When both distance and direction are considered, motion can be represented by a vector. A vector is a measurement that has both size and direction. It may be represented by an arrow. If you are representing motion with an arrow, the length of the arrow represents distance, and the way the arrow points represents direct... |
if you are riding on a bus with a friend, you can tell you are moving by observing the motion of | (A) your friend in the seat beside you (B) the bus driver at the front of the bus (C) objects like trees and houses outside the windows (D) two of the above | C | Theres more to motion than objects simply changing position. Youll see why when you consider the following example. Assume that the school bus pictured in the Figure 1.2 passes by you as you stand on the sidewalk. Its obvious to you that the bus is moving, but what about to the children inside the bus? The bus isnt mov... |
in question 6, what is your frame of reference for detecting the motion of the bus? | (A) your friend (B) the bus driver (C) objects outside the windows (D) two of the above | C | Assume that a school bus, like the one in Figure 12.2, passes by as you stand on the sidewalk. Its obvious to you that the bus is moving. It is moving relative to you and the trees across the street. But what about to the children inside the bus? They arent moving relative to each other. If they look only at the other ... |
in question 6, the bus drivers frame of reference is the passenger directly behind him. | (A) true (B) false | B | Assume that a school bus, like the one in Figure 12.2, passes by as you stand on the sidewalk. Its obvious to you that the bus is moving. It is moving relative to you and the trees across the street. But what about to the children inside the bus? They arent moving relative to each other. If they look only at the other ... |
in question 6, the frame of reference of an outside observer of the bus might be a house across the street. | (A) true (B) false | A | Assume that a school bus, like the one in Figure 12.2, passes by as you stand on the sidewalk. Its obvious to you that the bus is moving. It is moving relative to you and the trees across the street. But what about to the children inside the bus? They arent moving relative to each other. If they look only at the other ... |
if you are sitting on a stationary bus, which frame of reference might may you think the bus has started moving? | (A) The car in the next lane starts moving (B) A passenger moves to the back of the bus (C) The bus driver turns to look through the windshield (D) none of the above | A | Assume that a school bus, like the one in Figure 12.2, passes by as you stand on the sidewalk. Its obvious to you that the bus is moving. It is moving relative to you and the trees across the street. But what about to the children inside the bus? They arent moving relative to each other. If they look only at the other ... |
people have been using sound to make music for thousands of years. | (A) true (B) false | A | People have been using sound to make music for thousands of years. They have invented many different kinds of musical instruments. Despite their diversity, however, musical instruments share certain similarities. All musical instruments create sound by causing matter to vibrate. The vibrations start sound waves moving ... |
there are a total of 50 different kinds of musical instruments. | (A) true (B) false | B | There are three basic categories of musical instruments: percussion, wind, and stringed instruments. You can read in the Figure 1.1 how instruments in each category make sound and change pitch. Q: Can you name other instruments in each of the three categories of musical instruments? A: Other percussion instruments incl... |
all musical instruments make sound by causing something to vibrate. | (A) true (B) false | A | People have been using sound to make music for thousands of years. They have invented many different kinds of musical instruments. Despite their diversity, however, musical instruments share certain similarities. All musical instruments create sound by causing matter to vibrate. The vibrations start sound waves moving ... |
when instruments change the frequency of sound waves, the sound changes | (A) pitch (B) amplitude (C) loudness (D) all of the above | A | People have been using sound to make music for thousands of years. They have invented many different kinds of musical instruments. Despite their diversity, however, musical instruments share certain similarities. All musical instruments create sound by causing matter to vibrate. The vibrations start sound waves moving ... |
categories of musical instruments include | (A) wind instruments (B) stringed instruments (C) percussion instruments (D) all of the above | D | There are three basic categories of musical instruments: percussion, wind, and stringed instruments. You can read in the Figure 1.1 how instruments in each category make sound and change pitch. Q: Can you name other instruments in each of the three categories of musical instruments? A: Other percussion instruments incl... |
blowing into a clarinet starts vibrations in a thin wooden | (A) reed (B) bell (C) key (D) none of the above | A | All sounds begin with vibrating matter. It could be the ground vibrating when a tree comes crashing down. Or it could be guitar strings vibrating when they are plucked. You can see a guitar string vibrating in Figure 20.2. The vibrating string repeatedly pushes against the air particles next to it. The pressure of the ... |
what was the first step in the development of solar car technology? | (A) development of a model solar car (B) design of a solar panel (C) invention of the solar cell (D) launch of the World Solar Challenge | C | New technologies such as 3-D printers often evolve slowly as new materials, designs, or processes are invented. Solar-powered cars are a good example. For several decades, researchers have been working on developing practical solar-powered cars. Why? Cars powered by sunlight have at least two important advantages over ... |
technology may include | (A) materials (B) devices (C) processes (D) all of the above | D | Technology is the application of knowledge to real-world problems. It includes methods and processes as well as devices like computers and cars. An example is the Bessemer process. It is a cheap method of making steel that was invented in the 1850s. It is just one of many technological advances that have occurred in ma... |
atoms of all elements have neutrons in their nucleus. | (A) true (B) false | B | A neutron is a particle inside the nucleus of an atom. It has no electric charge. Atoms of an element often have the same number of neutrons as protons. For example, most carbon atoms have six neutrons as well as six protons. This is also shown in Figure below . |
neutrons have a negative electrical charge. | (A) true (B) false | B | Unlike protons and electrons, which are electrically charged, neutrons have no charge. In other words, they are electrically neutral. Thats why the neutrons in the diagram above are labeled n0 . The zero stands for zero charge. The mass of a neutron is slightly greater than the mass of a proton, which is 1 atomic mass ... |
the mass of a neutron is close to the mass of | (A) an electron (B) a proton (C) the nucleus (D) none of the above | B | Unlike protons and electrons, which are electrically charged, neutrons have no charge. In other words, they are electrically neutral. Thats why the neutrons in the diagram above are labeled n0 . The zero stands for zero charge. The mass of a neutron is slightly greater than the mass of a proton, which is 1 atomic mass ... |
a neutron has about the same diameter as a proton. | (A) true (B) false | A | Unlike protons and electrons, which are electrically charged, neutrons have no charge. In other words, they are electrically neutral. Thats why the neutrons in the diagram above are labeled n0 . The zero stands for zero charge. The mass of a neutron is slightly greater than the mass of a proton, which is 1 atomic mass ... |
atoms of the same element may differ in their numbers of neutrons. | (A) true (B) false | A | Some atoms of the same element may have different numbers of neutrons. For example, some carbon atoms have seven or eight neutrons instead of the usual six. Atoms of the same element that differ in number of neutrons are called isotopes. Many isotopes occur naturally. Usually one or two isotopes of an element are the m... |
each neutron contains | (A) three quarks and three gluons (B) two up quarks and one down quark (C) two quarks and one gluon (D) two gluons and one quark | A | A neutron is a particle inside the nucleus of an atom. It has no electric charge. Atoms of an element often have the same number of neutrons as protons. For example, most carbon atoms have six neutrons as well as six protons. This is also shown in Figure below . |
without an unbalanced force acting on it, a moving object will | (A) keep moving (B) maintain a constant speed (C) keep going in the same direction (D) all of the above | D | To change the motion of an object, inertia must be overcome by an unbalanced force acting on the object. The unbalanced force that starts Laurens cousins rolling along on the skateboard is applied by Lauren when she gives it a push. Once an object starts moving, inertia keeps it moving without any additional force bein... |
if you dont try to stop a rolling skateboard, it will keep moving forever. | (A) true (B) false | B | To change the motion of an object, inertia must be overcome by an unbalanced force acting on the object. The unbalanced force that starts Laurens cousins rolling along on the skateboard is applied by Lauren when she gives it a push. Once an object starts moving, inertia keeps it moving without any additional force bein... |
pressing down on one side of a skateboard causes it to turn toward the opposite side. | (A) true (B) false | A | Coreys friend Jerod likes to skate on the flat banks at Newtons Skate Park. Thats Jerod in the Figure 1.3. As he reaches the top of a bank, he turns his skateboard to go back down. To change direction, he presses down with his heels on one edge of the skateboard. This causes the skateboard to turn in the opposite direc... |
if you run into a curb on a skateboard, you will fall forward off your skateboard because there is an unbalanced force applied to your body. | (A) true (B) false | B | Did you ever ride a skateboard? Even if you didnt, you probably know that to start a skateboard rolling over a level surface, you need to push off with one foot against the ground. Thats what Coreys friend Nina is doing in this picture 1.1. Do you know how to stop a skateboard once it starts rolling? Look how Ninas fri... |
isaac newton was the first person to observe the effects of gravity. | (A) true (B) false | B | People have known about gravity for thousands of years. After all, they constantly experienced gravity in their daily lives. They knew that things always fall toward the ground. However, it wasnt until Sir Isaac Newton developed his law of gravity in the late 1600s that people really began to understand gravity. Newton... |
newton would agree that all objects on earth exert a gravitational pull on earth. | (A) true (B) false | A | Newton was the first one to suggest that gravity is universal and affects all objects in the universe. Thats why his law of gravity is called the law of universal gravitation. Universal gravitation means that the force that causes an apple to fall from a tree to the ground is the same force that causes the moon to keep... |
newtons law of gravity was the first scientific law that applied to everything in the universe. | (A) true (B) false | A | Newton was the first one to suggest that gravity is universal and affects all objects in the universe. Thats why Newtons law of gravity is called the law of universal gravitation. Universal gravitation means that the force that causes an apple to fall from a tree to the ground is the same force that causes the moon to ... |
the equation that newtons developed to calculate the force of gravity between two gm1m 2 . in this equation, the letter g represents the objects is fg = | (A) force of gravity (B) combined masses of the objects (C) universal gravitational constant (D) none of the above | C | Newtons second law of motion explains the weight of objects. Weight is a measure of the force of gravity pulling on an object of a given mass. Its the force (F) in the acceleration equation that was introduced above: a= F m This equation can also be written as: F = ma The acceleration due to gravity of an object equals... |
what does the letter r represent in the equation in question 7? | (A) rotation (B) revolution (C) distance (D) none of the above | C | The population growth rate is how fast a population is growing. The letter r stands for the growth rate. The growth rate equals the number of new members added to the population in a year for each 100 members already in the population. The growth rate includes new members added to the population and old members removed... |
acceleration occurs whenever an object is acted on by an unbalanced force. | (A) true (B) false | A | A change in an objects motionsuch as Xander speeding up on his scooteris called acceleration. Acceleration occurs whenever an object is acted upon by an unbalanced force. The greater the net force acting on the object, the greater its acceleration will be, but the mass of the object also affects its acceleration. The s... |
factors that affect the acceleration of an object include the | (A) net force acting on the object (B) object’s speed (C) object’s mass (D) two of the above | D | Whenever an object speeds up, slows down, or changes direction, it accelerates. Acceleration occurs whenever an unbalanced force acts on an object. Two factors affect the acceleration of an object: the net force acting on the object and the objects mass. Newtons second law of motion describes how force and mass affect ... |
there is a direct relationship between acceleration and mass. | (A) true (B) false | B | Newtons second law shows that there is a direct relationship between force and acceleration. The greater the force that is applied to an object of a given mass, the more the object will accelerate. For example, doubling the force on the object doubles its acceleration. The relationship between mass and acceleration, on... |
increasing the force acting on an object increases its acceleration. | (A) true (B) false | A | Newtons second law shows that there is a direct relationship between force and acceleration. The greater the force that is applied to an object of a given mass, the more the object will accelerate. For example, doubling the force on the object doubles its acceleration. The relationship between mass and acceleration, on... |
if the net force acting on an object increases by 50 percent, then the acceleration of the object will | (A) decrease by 50 percent (B) increase by 100 percent (C) stay the same (D) none of the above | D | Newtons second law shows that there is a direct relationship between force and acceleration. The greater the force that is applied to an object of a given mass, the more the object will accelerate. For example, doubling the force on the object doubles its acceleration. The relationship between mass and acceleration, on... |
which equation shows the relationships among acceleration, mass, and net force? | (A) acceleration = net force x mass (B) acceleration =- net force/mass (C) acceleration = mass/net force (D) none of the above | B | Newton determined that two factors affect the acceleration of an object: the net force acting on the object and the objects mass. The relationships between these two factors and motion make up Newtons second law of motion. This law states that the acceleration of an object equals the net force acting on the object divi... |
forces always act in pairs. | (A) true (B) false | A | Two forces may act on an object in the same direction. You can see an example of this in Figure 13.5. After the man on the left lifts up the couch, he will push the couch to the right with a force of 25 newtons. At the same time, the man to the right is pulling the couch to the right with a force of 20 newtons. When tw... |
the reaction to an action is always | (A) equal in strength to the action (B) in the same direction as the action (C) in the opposite direction to the action (D) two of the above | D | Newtons third law of motion states that every action has an equal and opposite reaction. This means that forces always act in pairs. First an action occurs, such as the skateboarders pushing together. Then a reaction occurs that is equal in strength to the action but in the opposite direction. In the case of the skateb... |
a stronger action always results in a stronger reaction. | (A) true (B) false | A | The forces involved in actions and reactions can be represented with arrows. The way an arrow points shows the direction of the force, and the size of the arrow represents the strength of the force. Look at the skateboarders in the Figure 1.1. In the top row, the arrows represent the forces with which the skateboarders... |
action and reaction forces always cancel each other out. | (A) true (B) false | B | Because action and reaction forces are equal and opposite, you might think they would cancel out, as balanced forces do. But you would be wrong. Balanced forces are equal and opposite forces that act on the same object. Thats why they cancel out. Action-reaction forces are equal and opposite forces that act on differen... |
action and reaction forces always act on the same object. | (A) true (B) false | B | Because action and reaction forces are equal and opposite, you might think they would cancel out, as balanced forces do. But you would be wrong. Balanced forces are equal and opposite forces that act on the same object. Thats why they cancel out. Action-reaction forces are equal and opposite forces that act on differen... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.