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All Textbook Solutions for Conceptual Physics: The High School Physics Program
Which will have the greater acceleration rolling down an incline—a bowling ball or a volleyball? Defend your answer.Any rolling object takes more time to roll down an inclined plane than a non-rolling object sliding without friction. Jim says this is because all the PE of the non-rolling object goes into translational KE, with none 'wasted' as rotational KE. John doesnt think a sliding object slides down an incline faster than a rolling object. With whom do you agree?Jim says that in race between a can of water and a can of ice rolling down an incline, the water filled can will win because the water inside slides' down the incline, while the ice is made to rotate, slowing its movement down the incline. John now agrees. Do you agree?Consider two rotating bicycle wheels, one filled with air and the other filled with water. Which would be more difficult to stop rotating? Explain.You sit in the middle of a large, freely rotating turntable at an amusement park. If you crawled toward the outer rim, would your rotational speed increase, decrease, or remain unchanged? What law of physics supports your answer?A sizable quantity of soil is washed down the Mississippi River and deposited in the Gulf of Mexico each year. What effect does this tend to have on the length of a day? (Hint: Relate this to a spinning skater who extends her arms outward.)If all of Earths inhabitants moved to the equator, how would this affect Earths rotational inertia? How would it affect the length of a day?If the worlds populations move to the North and South Poles, would the length of a day increase, decrease, or stay the same?If the polar ice caps of Earth were to melt, the oceans everywhere would be deeper by about 30 m. What effect would this have on Earths rotation?A toy train is initially at rest on a track fastened to a bicycle wheel, which is free to rotate. How does the wheel respond when the train moves clockwise? When the train backs up? Does the angular momentum of the wheel-train system change during these maneuvers? How would the resulting motions be affected if the train were much more massive than the track? If the track were much more massive?Why does a typical small helicopter with a single main rotor have a second small rotor on its tail? Describe the consequence if the small rotor fails in flight.We believe our galaxy was formed from a huge cloud of gas. The original cloud was far larger than the present size of the galaxy, more or less spherical, and rotating very much more slowly than the galaxy is now. In this sketch we see the original cloud and the galaxy as it is now (seen edgewise). Explain how the law of gravitation and the conservation of angular momentum contribute to the galaxys present shape and why it rotates faster now than when it was a larger, spherical cloud.An occupant inside a rotating space habitat of the future will feel pulled by artificial gravity against the outer wall of the habitat (which becomes the 'floor'). What physics provides an explanation?Explain why the faster Earth spins, the less a person weighs, whereas the faster a space station spins, the more a person weighs.What happens to the rotational inertia of a simple pendulum when the mass of the bob is doubled and the length of the pendulum is halved? (See Figure 12.6.)What happens to the rotational inertia of a simple pendulum when both the mass of the bob and the length of the pendulum are doubled?What happens to the rotational inertia of a simple pendulum when both the mass of the bob and the length of the pendulum are halved?A pair of identical 1000-kg space pods in outer space are connected to each other by a 900-m-long cable. They rotate about a common point like a spinning dumbbell as shown in the figure. Calculate the rotational inertia of each pod about the axis of rotation. What is the rotational inertia of the two-pod system about its midpoint? Express your answers in kgm2.The two-pod system in the previous question rotates 1.2 RPM to provide artificial gravity for its occupants. If one of the pods pulls in 100 m of cable (bringing the pods closer together), what will be the systems new rotation rate?Gretchen moves at a speed of 6.0 m/s when sitting on the edge of a horizontal rotating platform of diameter 4.0 m. Her mass is 45 kg. Show that her angular momentum about the center of the platform will be 540kgm2/s.If a trapeze artist rotates twice each second while sailing through the air, and contracts to reduce her rotational inertia to one-third, how many rotations per second will result?A 0.60-kg puck revolves at 2.4 m/s at the end of a 0.90-m string on a frictionless air table. Show that when the string is shortened to 0.60 m the speed of the puck will be 3.6 m/s.Gather a selection of canned foods. Predict which will roll faster down an incline. Compare liquids (which slide or slosh rather thin roll inside the can) and solids. Roll the cans to test your predictions. Describe your results.In Newtons insight, what did a falling apple have in common with the moon?In what sense does the moon 'fall'?How does the tangential velocity of a planet relate to it orbiting around the sun?What is the gravitational force between two 1-kilogram bodies that are 1 meter apart?5AIn what way does the force of gravity between two objects depend on their masses?How does the force of gravity depend on the distance between two objects?How does the force of gravity between two bodies change when the distance between them is doubled?How does the intensity of light, radiation, and sound change when a point source is twice as far away?Do you escape from Earths gravity if you're above the atmosphere? By being on the moon? Defend your answers.At what distance away from Earth is Earths gravitational force on an object zero?12AWhat is the value of Earths gravitational field at the center of Earth?If you stepped into a hole that passed completely through Earth, you'd oscillate down and up. How long would a one-way trip take? How long would a round trip take?Would the gauge inside a bathroom scale be more compressed or less compressed if you weighed yourself in an elevator that accelerated upward? Downward?Do tides depend more on the strength of gravitational pull or on the difference in strengths? Explain.Why are ocean tides higher at the time of a full moon?18A19AWhat was the cause of perturbations discovered in the orbit of Planet Uranus?The planet and its moon gravitationally attract each other. Rank gravitational attractions between them from greatest to least.Calculate the force of gravity on a 1-kg mass at Earths surface. The mass of Earth is 61024kg, and its radius is 6.4106m.Calculate the force of gravity on the same 1-kg mass if it were 6.4106m above Earths surface (that is, if it were 2 Earth radii from Earths center).Calculate the force of gravity between Earth mass=6.01024kg and the moon mass=7.41022kg. The average Earth—moon distance is 3.8108m.Calculate the force of gravity between Earth and the sun (sunsmass=2.01030kg; average Earth—sun distance=1.51011m).Calculate the force of gravity between a newborn baby mass=4kg and the planet Mars mass=6.41023kg, when Mars is at its position closest to Earth distance=81010m.Calculate the force of gravity between a newborn baby of mass 4 kg and the obstetrician of mass 75 kg, who is 0.3 m from the baby. Which exerts more gravitational force on the baby, Mars or the obstetrician? By how much?Comment on whether or not this label on a consumer product should be cause for concern. CAUTION: The mass of this product affects every other mass in the universe, with an attractive force that is proportional to the product of the masses and inversely proportional to the square of the distance between them.Gravitational force acts on all objects in proportion to their masses. Why, then, doesnt a heavy object fall faster than a lighter one? (Is the answer something you learned much earlier?)Irene says that Earths force of gravity is stronger on a piece of iron than on a piece of wood of the same mass. Do you agree? Defend your answer.Stephan says that the force of gravity is stronger on a piece of paper after its crumpled. His classmates disagree, so Stephan 'proves' his point by dropping two pieces of paper, one crumpled and the other not. Sure enough, the crumpled piece falls faster. Has Stephan proven his point? Explain.Earth and the moon are gravitationally attracted to each other. Does the more massive Earth attract the moon with a greater force, the same force, or less force than the moon attracts Earth?What is the magnitude and direction of the gravitational force that acts on a woman who weighs 500 N at the surface of Earth?If the gravitational forces of the sun on the planets suddenly disappeared, in what kind of paths would the planets move?The moon 'falls' 1.4 mm each second. Does this mean that it gets 1.4 mm closer to Earth each second? Would it get closer if its tangential velocity were reduced? Explain.If the moon were twice as massive, would the attractive force of Earth on the moon be twice as large? Of the moon on Earth?The weight of an apple near the surface of Earth is 1 N. What is the weight of Earth in the gravitational field of the apple?A friend proposes an idea for launching space probes that consists of boring a hole completely through Earth. Your friend reasons that a probe dropped into such a hole would accelerate all the way through and shoot like a projectile out the other side. Defend or oppose the reasoning of your friend.If you stand on a shrinking planet, so that in effect you get closer to its center, your weight will increase. But if you instead burrow into the planet and get closer to its center, your weight will decrease. Explain.If you were unfortunate enough to be in a freely falling elevator; you might notice the bag of groceries you were carrying hovering in front of you, apparently weightless. Cite the frames of reference in which the groceries would be falling, and those in which they would not be falling.What two forces act on you in a moving elevator? When are these forces equal in magnitude, and when are they not?A friend says that astronauts in orbit are weightless because they're beyond the pull of Earths gravity. Correct your friends ignorance.The sun exerts almost 200 times more force on the oceans of Earth than the moon does. Why then, is the moon more effective in raising tides?From a point of view at the sun, does the moon circle Earth, or does Earth circle the moon?What would be the effect on Earths tides if the diameter of Earth were larger than it is? If Earth were as it presently is, but the moon were larger—with the same mass?Whenever the ocean tide is unusually high, will the following low tide be unusually low? Defend your answer in terms of conservation of water.' (If you slosh water in a tub so that it is extra deep at one end, will water at the other end be extra shallow?)The human body is more than 50% water. Is it likely that the moons gravitational pull causes any significant biological tides—cyclic changes in water flow among the bodys fluid compartments? (Hint: Is any part of your body appreciably closer to the moon than any other part? Is there a difference in lunar pulls?)A black hole is no more massive than the star from which it collapsed. Why then, is gravitation so intense near a black hole?Which requires more fuel—a rocket going from Earth to the moon, or a rocket coming from the moon to Earth? Why?50AThe planet Jupiter is about 300 times as massive as Earth, but an object on its surface would weigh only 2.5 times as much as it would on Earth. Can you come up with an explanation? (Hint: Let the terms in the equation for gravitational force guide your thinking.)Some people dismiss the validity of scientific theories by saying they are 'only theories. The law of universal gravitation is a theory. Does this mean that scientists still doubt its validity? Explain.Equate your weight mg to Newtons equation for gravitational force, GmMR2 where M is the mass of Earth and R is Earths radius. Show that acceleration of free fall is g=GMR2Isabella drops a chunk of iron of mass m from the roof of her high school and it accelerates at g. Then she ties two chunks of iron together, of mass 2m. Show that when she drops the double chunk, the acceleration of fall is also g.The symbol g can mean acceleration due to gravity or gravitational field strength. Show that the units of g can be expressed as either m/s2 or N/kgBy what factor would your weight change if the Earths diameter were doubled and its mass were also doubled?Find the change in the force of gravity between two objects when both masses are doubled and the distance between them is also doubled.If you stood atop a ladder that was so tall that you doubled your distance from Earths center, how would your weight compare with its present value?Suppose you stood atop a ladder that was so tall that you were three Earth radii from Earths center. Show that your weight would be one ninth its present value.60ABy what factor does the force of gravity between two planets change when masses remain the same but the distance between them is increased by four?By what factor does the force of gravity between two planets change when the masses remain the same, but the distance between them is decreased by four?By what factor does the force of gravity between two planets change when the masses of the planets remain unchanged, but the distance between them is decreased by five?Many people mistakenly believe that the astronauts that orbit the Earth are 'above gravity.' Earths mass is 61024kg, and its radius is 6.38106m6380km. Use the inverse-square law to show that in space-shuttle territory, 200 kilometers above Earths surface, the force of gravity on a shuttle is about 94% that at Earths surface.If we drop a ball from rest, how far will it fall vertically in the first second? If we instead move our hand horizontally and drop it (throw it), how far will it fall vertically in the first second?What do the distances 8000 m and 5 m have to do with a line tangent to Earths surface?How does the direction of motion of a satellite in circular orbit compare with the curve of Earths surface?Why doesnt gravitational force change the speed of a satellite in circular orbit?Does the period of a satellite in a circular orbit increase or decrease as its distance from Earth increases?Describe an ellipse.Why does gravitational force change the speed of a satellite in elliptical orbit?a. Where in an elliptical orbit is the speed of a satellite maximum? b. Where is it minimum?The sum of PE and KE for a satellite in a circular orbit is constant. Is this sum also constant for a satellite in an elliptical orbit?Why does the force of gravity do no work on a satellite in circular orbit, but does do work on a satellite in an elliptical orbit?What scientist gathered accurate data on planetary paths around the sun? What scientist discovered that the paths are ellipses? What scientist explained the ellipses?12AWhat is the mathematical relationship between how long it takes a planet to orbit the sun and its distance from the sun?a. What is the minimum speed for circling Earth in close orbit? b. What is the maximum speed in an orbit that comes close to Earth at one point? c. What happens to a satellite traveling faster than the maximum speed described in part (b)?Neglecting air resistance, what will happen to a projectile that is fired vertically at 8 km/s? At 12 km/s?a. How fast would a particle have to be ejected from the sun to leave the solar system? b. What speed would be needed if an ejected particle started at a distance from the sun equal to Earths distance from the sun?17AAlthough the escape speed from the surface of Earth is 11.2 km/s, couldnt a rocket with enough fuel escape at any speed? Why or why not?How was Pioneer 10 able to escape the solar system with an initial speed less than escape speed?The dashed lines show three circular orbits about Earth. Rank the following quantities for these orbits from greatest to least. a. orbital speed b. time for orbiting EarthFour satellites in circular orbit about Earth have the following characteristics: (A) m=4000kg; height 300 km (B) m=5000kg; height 350 km (C) m=4000kg; height 400 km (D) m=5000kg; height 500 km a. Rank the satellites' orbital speeds from greatest to least. b. Rank the satellites' times for orbiting Earth from greatest to least. c. Does mass affect your answers to parts (a) and (b)?The positions of a satellite in elliptical orbit are indicated. Rank these quantities from greatest to least. a. gravitational force b. speed c. momentum d. KE e. PE f. total energy KE+PE g. accelerationKepler tells us that a planet sweeps out equal areas in equal intervals of time. Four such equal-area triangles' are shown. Rank these quantities from greatest to least. a. average speed during the time interval b. acceleration during the time intervalA satellite can orbit at 5 km above the moon, but not at 5 km above Earth. Why?Does the speed of a satellite around Earth depend on its mass? Its distance from Earth? The mass of Earth?If a cannonball is fired from tall mountain, gravity changes its speed all along its trajectory. But if it is fired fast enough to go into circular orbit, gravity does not change its speed at all. Why?Does gravity do any network on a satellite in an elliptical orbit during one full orbit? Explain your answer.A geosynchronous Earth satellite can remain almost directly overhead in Singapore, but not San Francisco, Chicago, or New York City. Why?If you stopped an Earth satellite dead in its tracks, it would simply crash into Earth. Why, then, dont the communications satellites that hover motionless above the same spot on Earth crash into Earth?In an accidental explosion, a satellite breaks in half while in circular orbit about Earth. One half is brought momentarily to rest. What is the fate of the half brought to rest? What is the speed of the other half? (Hint: Think momentum conservation.)31AWhy do you suppose that sites close to the equator are preferred for launching satellites? (Hint: Look at the spinning Earth from above either pole and compare it to a spinning turntable.)Why do you suppose that a space shuttle is sent into orbit by firing it in an easterly direction (the direction in which Earth spins)?Consider two planets: Mercury, close to the sun, and Uranus, far from the sun. Which of these planets has a period shorter than Earths period around the sun? Which has a period longer than Earths?What is the maximum possible speed of impact upon Earths surface for a faraway object initially at rest that falls to Earth due only to Earths gravity?Why does most of the work done in launching a rocket take place when the rocket is still close to Earths surface?If Pluto were somehow stopped short in its orbit, it would fall into the sun rather than around it. About how fast would it be moving when it hit the sun?If an astronaut in an orbiting space shuttle wished to drop something to Earth, how could this be accomplished?If Earth somehow acquired more mass, with no change in its radius, would escape speed be less than, equal to, or more than 11.2 km/s? Why?Calculate the speed in m/s at which Earth revolves around the sun. Note: The orbit is nearly circular.A spaceship in circular orbit about the moon is 2.0106m from its center. a. Show that the period of the spaceship is 2.2 h. b. Show that the speed of the spaceship relative to the moon is about 5800 km/h.Calculate the speed in m/s at which the moon revolves around Earth. Note: The orbit is nearly circular.43AAn orbiting satellite of mass m is pulled toward Earth by a force ma. Equate ma to the force in Newtons equation for universal gravitation and show that the satellites acceleration is a a=GMd2The force of gravity between Earth and an Earth satellite is given by F=GmMd2, where m is the mass of the satellite, M is the mass, of Earth, and d is the distance between the satellite and the center of Earth. If the satellite follows a circular orbit, the force keeping it in orbit must, be the centripetal force, given by F=mv2r. Equate the two expressions for force to show that the speed v=GMd.Use the result of Question 45 (now with the sun instead of Earth as the center of force) to calculate the speed in m/s at which Earth revolves about the sun. Assume Earths orbit is nearly circular.In 1610, Galileo discovered four moons of Jupiter. (Today we know that there are more than 60!) 10, the innermost of the moons observed by Galileo, is 1.5108m from Jupiters center and has a period of 1.5105s. Calculate Jupiters mass.A planet in a circular orbit takes a time T to orbit its sun at a radial distance r. In terms of r and T, how fast is the planet moving in its orbit?49AUse the equation T=2r3GM to show that the period of the space shuttle 200 km (200,000 m) above Earths surface is about 90 minutes. The radius of Earth is 6370 km (6,370,000 m).What is space-time?Can you travel while remaining in one place in space? Explain.Does light travel through space? Through time? Through both space and time?What is time dilation?5A6A7AThe path of light in a vertical 'light clock' in a high-speed spaceship is seen to be longer when viewed from a stationary frame of reference. Why, then, does the light not appear to be moving faster?If we view a passing spaceship and see that the inhabitants' time is running slow, how do they see our time running?If you were traveling in a high-speed rocket ship, would clocks on board appear to you to be running slow? Defend your answer.11AWhat are the present-day obstacles to interstellar space travel?13A14AIf you were traveling in a high-speed spaceship, would metersticks on board appear contracted to you? Defend your answer.16A17AIf a spaceship moves away from you at half the speed of light and fires a rocket away from you at half the speed of light relative to the spaceship, common sense may tell you the rocket moves at the speed of light relative to you. But it doesnt! The relativistic addition of velocities (not covered in the chapter) is given by v=v1+v21+v1v2c2 Substitute 0.5cfor both v1 and v2 and show that the velocity, v, of the rocket relative to you is 0.8c.If the spaceship in question 18 somehow travels at c relative to you, and it somehow fires its rocket at c relative to itself, use the equation to show that the speed of the rocket relative to you is still c!Substitute small values of v1 and v2 in the preceding equation and show for everyday speeds that v is practically equal to v1+v2.If you were in a smooth-riding train with no windows, could you sense the difference between uniform motion and rest? Between accelerated motion and rest? Explain how you could do this with a bowl filled with water.Suppose you're playing catch with a friend in a moving train. When you toss the ball in the direction the train is moving, how does the speed of the ball appear to an observer standing at rest outside the train? (Does it increase or appear the same as if the observer were riding on the train?)23APeople who ride in a bus all know they're moving through space. But you know that they're also moving through something else. What else are they moving through?25A26A27A28AIf you were in a high-speed spaceship traveling away from Earth at a speed close to that of light, would you measure your normal pulse to be slower, the same, or faster? How would your measurements of pulses of friends back on Earth be if you could monitor them from your ship? Explain.30A31A32AJoe Burpy is 30 years old and has a daughter who is 6 years old. Joe leaves on a space bus and takes a 5-year (space-bus time) round-trip at 0.99c. How old will he and his daughter be when he returns?Assume that your heart normally beats once every second, and that you are in a spaceship that moves past Earth at 0.6c. a. What time do you measure between your own heartbeats? b. Show that your heartbeats are measured by someone on Earth to be 1.25 s apart. c. As you and the spaceship whiz past Earth, you make similar measurements on Earthlings who measure their own heart-beats to be 1 s apart. How much time do you measure between their heartbeats?Thomas, a rhino, is 2.5 meters long when at rest. a. How long will you measure him to be when hes running by at 0.80c? b. Show that you would measure a time of 6.3 ns for the length of his body to pass you.A ship whizzes by you at 0.60c. Someone aboard is making a 3-minute egg for breakfast. a. What cooking time will you measure for the egg? b. Why should you not be surprised when the egg turns out to be perfectly cooked, rather than overcooked?Before leaving the planet Hislaurels for a starship voyage, you pack a meterstick in your luggage. After the ship has settled down to a steady speed of 0.50c, you take the meterstick out of your bag. a. How long will you measure the meterstick to be? b. If the meterstick is moving parallel to an observer resting on Hislaurels, how long will the observer measure the meterstick?You are standing facing forward on the floor of your starship, which is moving at 0.80c relative to Earth. Before you left Earth, you measured your feet to be 25 cm long. a. People on Earth will now measure your feet to be how long? b. Do you need to be concerned now that the shoes that you packed for the trip will be too big?Pinocchio is concerned that Gepetto will see his long hose and realize that he has been lying. So Pinocchio decides to run past Gepetto fast enough that his 10-inch long nose will be seen by Gepetto to be only 2 inches long. a. How fast must Pinocchio run? b. When running past Gepetto, will Pinocchio see Gepettos nose shortened?Lizzie is scooting down the Interstate at 17 percent of the speed of light and measures the distance between mileposts to be less than 5,280 feet. a. What distance does she measure? b. What distance would she measure at 32 percent the speed of light?What would be the momentum of an object if it were pushed to the speed of light?2A3A4AWhat is the numerical quantity of the ratio rest energy/rest mass?6A7AWhen the mass of something decreases, does it emit or absorb energy?Compare the relative amounts of mass lost in nuclear reactions and in chemical reactions.10AWhat results when low everyday speeds are used in the relativistic equations for time and length?Do the equations of Newton and Einstein overlap, or is there a sharp break between them?13A14AWhat is a geodesic?According to general relativity, in what paths do planets travel as they orbit the sun?What is the evidence for light bending near the sun?Which runs faster, a clock at the top of the Sears Tower in Chicago or a clock on the shore of Lake Michigan?19ADoes Einsteins theory of gravitation invalidate Newtons theory of gravitation? Explain.Electrons are fired at different speeds through a magnetic field and are bent from their straight-line paths to hit the detector at the points shown. Rank the speeds of the electrons from highest to lowest.To an Earth observer, metersticks on three spaceships are seen to have these lengths. Rank the speeds of the spaceships relative to Earth from highest to lowest.What happens to the momentum of a massive object as its speed gets closer and closer to the speed of light?When a charged particle moves through a magnetic field, what is the evidence that its momentum is greater than the value mv?25ADoes a fully charged flashlight battery weigh more than the same battery when dead? Defend your answer.Two safety pins, identical except that one is latched and one is unlatched, are placed in identical acid baths. After the pins are dissolved, what, if anything, is different about the two acid baths?A friend says that the equation E=mc2 has relevance to nuclear power plants, but not to fossil-fuel power plants. Another friend looks to see if you agree. What do you say?29AAn astronaut awakes in her closed capsule, which actually sits on the moon. Can she tell whether her weight is the result of gravitation or of accelerated motion? Explain.An astronaut is provided 'gravity' when the ships engines are activated to accelerate the ship. This requires the use of fuel. Is there a way to accelerate and provide 'gravity' without the sustained use of fuel? (Hint: Recall simulated gravity in Chapter 12.)What happens to the separation distance between two people if they both walk north at the same rate from two locations on Earths equator?Your friend whimsically says that at the North Pole, a step in any direction is a step south. Do you agree?We readily note the bending of light by reflection and refraction, but why are we not aware of the bending of light by gravity?35AYour friend says that light passing the sun is bent whether or not Earth experiences a solar eclipse. Do you agree or disagree, and why?In 2004 when Mercury passed between the sun and Earth, light was not appreciably bent as it passed Mercury. Why?During the first second of its flight, a bullet fired horizontally drops a vertical distance of 4.9 m from its otherwise straight-line path in a gravitational field of 1 g. By What distance would a beam of light drop from its otherwise straight-line path if it traveled in a uniform field of 1 g for 1 s? For 2 s?39ADo you age faster at the top of a mountain or at sea level?41AIs light emitted from the surface of a massive star red-shifted or blue-shifted by gravity?From our frame of reference on Earth, objects slow to a stop as they approach black holes in space because time gets infinitely stretched by the strong gravity near the black hole. If astronauts accidentally falling into a black hole tried to signal back to Earth by flashing a light, what kind of wave-lengths of light would best be looked for in Earth-based telescopes?Gravitational waves are difficult to detect. Is this due to having long wavelengths or short ones? High energy or low energy?A 100-watt light bulb consumes 100 joules of energy every second. How long could you burn that light bulb from the energy in one penny, which has a mass of 0.003 kg? (Assume all the pennys mass is converted to energy.)46A47A1A2A3AFrom where did the heaviest elements originate?5AHow does the age of most atoms compare with the age of the solar system?What is meant by the statement that you dont 'own' the atoms that make up your body?What causes dust particles to move with Brownian motion?Individual atoms cannot be seen with visible light; yet there is an image of individual atoms in Figure 17.4. Explain.What is the purpose of a model in science?Distinguish between an atom and a molecule.12Aa. Cite an example of a substance that is made of molecules. b. Cite a substance that is made of atoms rather than molecules.14A15A16A17A18A19A20A21A22A23A24A25AWhat is the periodic table of the elements?27A28A29AIn terms of electrical conduction, how does a plasma differ from a gas?31AHow many individual atoms are in a water molecule?33A34A35A36AIf no molecules in a body could escape, would the body have any odor?A kitten will add several kilograms to its mass as it grows into a full-sized cat. From where do the atoms that make up this added mass originate?39A40A41A42AWhat element will result if a proton is added to the nucleus of carbon? (See periodic table.)If two protons and two neutrons are removed from the nucleus of an oxygen atom, what nucleus remains?45AWhat element results if one of the neutrons in a nitrogen nucleus is converted by radio-active decay into a proton?47A48A49AYou could swallow a capsule of the element germanium without harm. But if a proton were added to each of the germanium nuclei, you would not want to swallow the capsule.51A52AWhen an atom loses an electron and becomes a positively charged ion, how significant is the change in the atoms mass?54A55A56AIs it possible to have a molecule that isnt a compound? Give an example.Is it possible to have a compound that isnt made up of molecules? Give an example.If you eat metallic sodium or inhale chlorine gas, you run a great risk of dying. When these two elements combine, however, you can safely sprinkle the resulting compound on your popcorn for better taste. What is going on?To become a negative ion, does an atom lose or gain an electron?To become a positive ion, does an atom lose or gain an electron?62AWhy dont equal masses of golf balls and table-tennis balls contain the same number of balls? Also, why dont equal masses of pure carbon and oxygen contain the same number of atoms?Which contains more atoms: 1 kg of lead or 1 kg of aluminum?In a gaseous mixture of hydrogen and oxygen molecules, both with the same average kinetic energy, which molecules move faster on average?66AIn what sense is it correct to say that much of a tree is solidified air?The phases of matter are solid, liquid, gas, and plasma. What does the addition or subtraction of heat have to do with changes of phase?69AShow that there are 16 grams of oxygen in 18 grams of water.Show that there are 4 grams of hydrogen in 16 grams of methane gas. (The chemical formula for methane is CH4.)72AA typical atom is around 21010m in diameter, while a typical bacterium is about 106m in diameter. How many atoms thick is the typical bacterium?74AHow does the arrangement of atoms differ in a crystalline and a noncrystalline substance?What evidence do we have for the microscopic crystal nature of some solids?