Physics Test #1

Roughly how many different elements are there? A) 100 B) 1000 C) many more than 1000 D) 20 E) 4

A) 100

A ball is moving at 20 m/s. If no forces act on it, then 5 seconds later the ballʹs speed will be A) 20 m/s. B) less than 20 m/s, but the precise answer cannot be found without further information. C) zero. D) more than 20 m/s, but the precise answer cannot be found without further information. E) None of the above.

A) 20 m/s

In words, 3.5 x 10^11 is (HINT: Write this number out before trying to answer the question.) A) 350 billion. B) 350 million. C) 35 billion. D) 3.5 trillion. E) 35 million.

A) 350 billion.

The figure shows a ball tied to a string and swung in a circle, clockwise. If the string suddenly breaks when the ball is in the position shown, which arrow best represents the initial direction of motion of the ball just after the string breaks? A) Arrow A. B) Arrow B. C) Arrow C. D) Arrow D. E) Arrow E.

A) Arrow A.

Evidence that things are made of atoms comes from A) Brownian motion. B) superconductivity. C) the fact that we can cut solid objects into smaller and smaller pieces. D) the way that laser beams pass through air. E) the fact that objects accelerate as they fall.

A) Brownian motion.

The chemical formula that represents the burning of wood or paper is A) C + O2 ⇒ CO2. B) C + O ⇒ CO. C) H2 + O ⇒ H2O. D) CO2 ⇒ C+O2. E) C + H2O ⇒ CH2O.

A) C + O2 ⇒ CO2.

The ʺfatherʺ of atomic materialism was A) Democritus. B) Newton. C) Kepler. D) Plato. E) Ptolemy

A) Democritus.

You are in distant space. A giant boulder, many times larger than you, is at rest in front of you. You tap the boulder lightly with a small hammer. What does the boulder do? A) It accelerates during the tap, up to a slow speed [slower than walking speed], then keeps moving at that speed. B) It accelerates both during and after the tap. C) It speeds up a little during the tap, but after the tap it soon [within a few minutes] slows down and comes to rest. D) It remains at rest. E) It accelerates during the tap, up to a high speed [faster than a fast-moving car], then keeps moving at that speed.

A) It accelerates during the tap, up to a slow speed [slower than walking speed], then keeps moving at that speed.

What is the scientific communityʹs view of the scientific value of astrology? A) It is unscientific, because it does not support its theories with clear and verifiable predictions about observations. B) Even though its predictions are occasionally inaccurate, it does deserve to be classified as a true science. C) It is unscientific, because its practitioners do not understand the principles of physics or astronomy. D) It is unscientific, because its predictions have been shown to be incorrect. E) It is scientific, even though it is not related to the ʺreal worldʺ of observed phenomena.

A) It is unscientific, because it does not support its theories with clear and verifiable predictions about observations.

What aspect of Keplerʹs theory would have horrified all astronomers before Kepler? A) Keplerʹs elliptical orbits. B) Keplerʹs simple circular orbits. C) The absence of any epicycles [or ʺcircles-within-circlesʺ]. D) The fact that Earth was no longer at the center. E) The fact that the Earth has a spherical shape in Keplerʹs theory.

A) Keplerʹs elliptical orbits.

According to Aristotelian physics, what outside influence acts on a stone while it falls? A) None. B) The Olympic gods. C) Acceleration. D) Fire. E) Gravity.

A) None.

How is the sun situated in the universe? A) The sun is just one of a large number of stars, and is located on the fringes of the Milky Way galaxy, which itself is just one galaxy among many galaxies. B) The sun is just one of many stars, and is located near the center of the rest of the stars in the universe. C) The sun is an isolated star that is far outside of all the galaxies in the universe, and is thus not part of any galaxy. D) Earth is at the center of the universe, and the sun orbits around the earth. E) The sun is at the center of the universe.

A) The sun is just one of a large number of stars, and is located on the fringes of the Milky Way galaxy, which itself is just one galaxy among many galaxies.

An artificial satellite moves at a steady 25,000 km/hr in a circular orbit around Earth. Is it accelerated? A) Yes, because its direction of motion is changing. B) Yes, because its speed is changing. C) No, because its speed is unchanging. D) No, because its direction of motion is unchanging. E) No, for both reasons C and D.

A) Yes, because its direction of motion is changing.

Is there any method by which we can detect individual atoms in the laboratory? A) Yes, by using microscopes based on the ʺmatter wavesʺ made by material particles such as electrons. B) No, because atoms are smaller than any physical wavelengths. C) No, because atoms are purely mathematical abstractions and not real physical objects. D) Yes, by using microscopes based on X‐rays rather than on light. E) Yes, by using very high power microscopes based on visible light of very short wavelength.

A) Yes, by using microscopes based on the ʺmatter wavesʺ made by material particles such as electrons.

A defining feature of ʺpseudoscienceʺ is A) it does not use proper scientific methodology. B) it is wrong. C) Both of the above. D) it is unusual, or odd. E) All of the above

A) it does not use proper scientific methodology.

A block of wood is given a brief push and then allowed to slide [without further pushing] along a table top, slowing down as it moves toward the east. As the block slides, A) its acceleration is toward the west. B) its velocity is toward the west. C) it has no acceleration. D) the net force on it is zero. E) its acceleration is toward the east.

A) its acceleration is toward the west

An auto is moving at a steady 50 mph up a long straight [constant ʺslopeʺ] incline. While it is on this incline, A) its acceleration is zero but its velocity is not zero. B) its velocity and acceleration are both zero. C) neither its velocity nor its acceleration are zero. D) its velocity is zero but its acceleration is not zero [i.e., it does have an acceleration]. E) it has the heebie-jeebies.

A) its acceleration is zero but its velocity is not zero.

An object is not accelerated if A) its speed and its direction of motion are both unchanging. B) it is acted upon by an external influence. C) its speed remains unchanged while its direction of motion changes. D) its speed changes while its direction of motion remains unchanged. E) both answers B and D are correct.

A) its speed and its direction of motion are both unchanging.

Democritus said that, although we imagine many things, ʺin reality, there are only atoms and the void.ʺ This idea could best be classified as A) materialism. B) rationalism. C) witticism. D) idealism. E) stoicism.

A) materialism

The length of your arm is closest to A) one meter. B) two meters. C) one kilometer. D) 100 meters. E) 10 centimeters

A) one meter.

You hold a 5-newton rock motionless in your hand. Regarding the forces on this rock, A) the net force on the rock is zero. B) there are no forces of any kind acting on the rock, because it is not moving. C) the net force on the rock is 5 newtons, directed upward. D) the downward force of gravity is balanced by the upward force of air resistance. E) the net force on the rock is 5 newtons, directed downward.

A) the net force on the rock is zero.

On the planet Venus, a Venusian picks up a stone and drops it into a deep hole. If it falls 3 m in 1 second, how far will it fall in 2 seconds? You can neglect Venusian air resistance. A) 9 m B) 12 m C) 20 m D) 6 m E) 15 m

B) 12 m

A girl lifts a ball by means of a string attached to the ball. The string exerts a 20 newton force on the ball. The ball weighs 8 newtons. The net force on the ball is A) zero. B) 12 newtons. C) 28 newtons. D) 20 newtons. E) 8 newtons.

B) 12 newtons.

You hold a 2 newton apple, having a mass of 0.2 kg, at rest in your hand. The net force on the apple is then A) 0.2 kg downward. B) 2 newtons downward. C) zero. D) 0.2 kg upward. E) 2 newtons upward

B) 2 newtons downward

An astronautʹs normal weight it 600 newtons. How much will she weigh while orbiting in a satellite at 12,000 kilometers [two earth radii] above the surface of Earth? A) zero B) 67 newtons C) 150 newtons D) 300 newtons E) 200 newtons

B) 67 newtons

What similarity did Isaac Newton perceive between a falling apple and the moon? A) The velocities of both are directed toward Earthʹs center. B) Both have forces on them toward Earthʹs center, and accelerations directed toward Earthʹs center. C) Both have forces on them toward Earthʹs center, but their accelerations are in different directions. D) Both have a velocities and accelerations directed toward Earthʹs center. E) Both have accelerations directed toward Earthʹs center, although the forces on them are in different directions.

B) Both have forces on them toward Earthʹs center, and accelerations directed toward Earthʹs center.

How did Newton deduce the dependence of the gravitational force on distance? A) By comparing the accelerations of objects falling to Earth from different heights. B) By calculating the moonʹs acceleration, and comparing it with the acceleration of a falling object. C) By comparing the time it takes Earth to orbit the sun with the time it takes to spin on its axis. D) By observing the way that a large gravitational pendulum moved. E) By measuring the gravitational attraction between large massive lead spheres in the laboratory.

B) By calculating the moonʹs acceleration, and comparing it with the acceleration of a falling object.

Mary pushes horizontally on a large, heavy table, which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesnʹt the table move? A) Newtonʹs law of force pairs says that there is an opposite ʺreaction forceʺ by the table against the instructorʹs hand, and this reaction force keeps the table from moving. B) Frictional forces by the floor on the table legs acted in the opposite direction to produce a net force of zero. C) The table had so much mass that its inertia kept it from moving. D) Although it is true that forces cause accelerations, they do not cause velocities; therefore, the table acquired no velocity. E) According to Newtonʹs meaning of the word ʺforce,ʺ the horizontal push against the table was not really a force.

B) Frictional forces by the floor on the table legs acted in the opposite direction to produce a net force of zero.

Object A has twice as much mass as object B. If you exert the same force on these two objects, how do their accelerations compare? A) Object A has twice as much acceleration as object B. Object A has twice as much mass as object B. If you exert the same force on these two objects, how do their accelerations compare? B) Object A has half as much acceleration as object B C) Object A has four times as much acceleration as object B. D) They both have the same acceleration. E) It is impossible to answer this without further details concerning the composition of the two object.

B) Object A has half as much acceleration as object B

According to current theories, how did the sunʹs planets get here? A) The sun was originally part of the two-star system, the second star split up into pieces, and these pieces developed into the planets. B) Part of the gas and dust that gathered together to form the sun went into orbit around the sun instead of falling into the sun, and this part formed the planets. C) A passing star tore off part of the sun, and this part separated into pieces to form the planets. D) Stars such as the sun, and planets such as those around the sun, all formed shortly after the big bang, and then gathered into ʺsolar systemsʺ such as we see today. E) After the sun had formed, it gathered fully-formed planets from various places as the sun moved through the galaxy.

B) Part of the gas and dust that gathered together to form the sun went into orbit around the sun instead of falling into the sun, and this part formed the planets.

Why is it so difficult to remove the lid from a vacuum-sealed jar? A) The vacuum inside the jar pulls inward on the lid, holding it firmly to the jar. B) The air pressure outside the jar pushes downward on the lid more strongly than the air pressure inside pushes upward on the lid. C) The higher pressure inside the jar pulls inward on the lid, holding it firmly to the jar. D) The air pressure inside the jar pushes upward on the lid more strongly than the air pressure outside pushes downward on the lid. E) The vacuum inside the jar pushes outward on the lid, holding it firmly to the jar.

B) The air pressure outside the jar pushes downward on the lid more strongly than the air pressure inside pushes upward on the lid.

Which of these is the correct definition for an ellipse? A) Each pair of points on the ellipse is the same distance from one fixed point. B) The sum of the distances of a point on the ellipse from two fixed points is the same, for each point on the ellipse. C) Each point on the ellipse lies on a smooth oval curve around one fixed point. D) All points on the ellipse are an equal distance apart. E) Each point on the ellipse is the same distance from one fixed point.

B) The sum of the distances of a point on the ellipse from two fixed points is the same, for each point on the ellipse.

When you are in a high-flying jet plane, does either your weight or your mass differ from their normal value as measured on the ground? A) No, both your weight and your mass are exactly the same as on the ground. B) Your weight is slightly reduced, but your mass is unchanged. C) Both your weight and your mass are slightly increased. D) Both your weight and your mass are slightly reduced. E) Your weight is slightly increased, but your mass is unchanged

B) Your weight is slightly reduced, but your mass is unchanged.

Suppose we subject a golf ball and a more massive lead ball to identical net forces. Then, compared to the golf ball, the lead ball must have A) a larger acceleration. B) a smaller acceleration. C) a larger speed. D) a smaller speed. E) None of the above answers is necessarily true.

B) a smaller acceleration.

The idea that everything is made of small particles is A) not yet widely accepted. The idea that everything is made of small particles is A) not yet widely accepted. B) a useful theory, but not known for certain. C) still only a tentative speculation made by many scientists. D) a useful idea that is known for certain to be true. E) false and no longer used by scientists.

B) a useful theory, but not known for certain.

Suppose you throw an apple horizontally. Neglecting air resistance, just after you release the apple from your hand, the net force on the apple is A) zero. Suppose you throw an apple horizontally. Neglecting air resistance, just after you release the apple from your hand, the net force on the apple is A) zero. B) directed downward. C) directed horizontally forward. D) directed horizontally backward. E) directed upward.

B) directed downward.

Which is lightest in weight? A) hydrogen atom B) electron C) water molecule D) proton E) oxygen atom

B) electron

A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. Galileo would say that the book stopped because A) of gravity. B) of friction. C) of its inertia. D) the ether slows it down to a stop. E) its natural motion is to come to rest.

B) of friction.

A certain grapefruit on Earth has a mass of one kilogram and a weight of one newton. When the grapefruit is on the moon its mass is A) less than ten newtons. B) one kilogram. C) less than one kilogram. D) ten newtons.

B) one kilogram.

One newton is about equal to A) 10 m/sec2. B) one-fourth pound. C) one-fourth kilogram. D) four pounds. E) one pound.

B) one-fourth pound.

Jack and Jill are both traveling straight north. Jack is walking at 4 mph, while Jill is riding a bicycle at 12 mph. Regarding their speeds and velocities: A) they have different speeds, but the same velocity. B) they have different speeds and different velocities. C) they both have the same speed and the same velocity. D) they both have the same speed but different velocities. E) None of the above.

B) they have different speeds and different velocities.

The very earliest Greek theory of the structure of the universe pictured Earth at the center with the planets revolving around it at an unchanging rate in simple circles. The Greeks later revised this theory because A) they didnʹt believe the theory was sufficiently beautiful to represent the eternal gods. B) they observed that the planetary motions are irregular and include such things as retrograde motion. C) certain observations led them to the conclusion that Earth has a spherical shape. D) they came to believe that the sun should be at the center of things. E) Actually, the Greeks never did abandon this theory‐‐the theory was not altered until the time of Copernicus.

B) they observed that the planetary motions are irregular and include such things as retrograde motion.

A ʺmegawattʺ is A) 100 watts. B) 1000 watts. C) 1,000,000 watts. D) 1,000,000,000 watts. E) None of the above.

C) 1,000,000 watts.

The number of atoms in the glucose molecule, C6H12O6, is A) 4. B) 3. C) 24. D) 48. E) cannot be determined from the given information.

C) 24.

A girl lifts a ball by means of a string attached to the ball. The string exerts a 30 newton force on the ball. The ball weighs 20 newtons and has a mass of 2 kilograms. The acceleration of the ball is A) 15 m/s2. B) zero. C) 5 m/s2. D) 25 m/s2. E) 10 m/s2

C) 5 m/s2

According to Aristotle, which of these is a ʺnaturalʺ or ʺunforcedʺ motion? A) A book coming to rest as it slides along the floor. B) A stone falling straight downward. C) Both of the above. D) Neither of the above.

C) Both of the above

An important similarity that Newton noticed between a falling apple and the moon was that A) the net force on both is toward the center of Earth. B) the accelerations of both are toward the center of Earth. C) Both of the above. D) the velocity of both is toward the center of Earth. E) All of the above.

C) Both of the above.

Planets do not move in precise ellipses, as had been thought by Kepler, because of A) influences due to the other planets. B) dust grains and other material that disturbs the orbits. C) Both of the above. D) Nonsense--the planets actually do move in precise ellipses.

C) Both of the above.

Which of the following describes an object that is accelerated? A) A car rounding a curve at a steady 80 km/hr B) A car slowing down while moving along a straight line C) Both of the above. D) A car moving up a straight hill [a hill whose ʺslopeʺ is unchanging] at a steady 80 km/hr, when the car is midway up the hill E) All of the above.

C) Both of the above.

Which of the following has the effect of reducing the gravitational force between two objects? A) Moving the two objects closer together. B) Increasing the mass of either one of the objects. C) Moving the two objects farther apart. D) None of these.

C) Moving the two objects farther apart.

The observed evidence we have for black holes includes A) visible light that is thought to come from the center of a black hole. B) observations of certain regions of space, larger than the largest known stars, that emit no light. C) X‐rays that are thought to come from gases that are outside of a black hole. D) X‐rays that are thought to come from the center of a black hole. E) temperature measurement of certain extremely cold stars that are thought to be black holes.

C) X‐rays that are thought to come from gases that are outside of a black hole.

The figure shows the moon orbiting around Earth. Suppose that the direction of the moonʹs motion is counter-clockwise. Is any net force exerted on the moon? A) Yes, in the direction of arrow B. B) Yes, in the direction of arrow A. C) Yes, in the direction of arrow C. D) No, because no net force is needed to keep an object moving. E) No, because the individual forces acting on the moon all balance out to yield a net force of zero.

C) Yes, in the direction of arrow C.

Is the moon accelerated? A) No, because there is no gravity in space. B) No, because the gravitational force on it is balanced by the centrifugal force. C) Yes, its acceleration is directed inward toward Earth. D) Yes, its acceleration is directed forward, along its direction of motion. E) Yes, its acceleration is directed outward away from Earth.

C) Yes, its acceleration is directed inward toward Earth.

While a rock is falling straight down it has A) an increasing acceleration. B) zero acceleration. C) a constant [or unchanging] acceleration. D) a decreasing acceleration. E) None of the above.

C) a constant [or unchanging] acceleration.

Mort weighs 700 newtons on Earth. He takes a low-orbit voyage in an Earth satellite. During the voyage his weight is A) a little more than 700 newtons. B) just a few newtons. C) a little less than 700 newtons. D) zero. E) 700 newtons.

C) a little less than 700 newtons.

Chemically, clean [nonpolluted] air is A) a liquid. B) an element. C) a mixture of different compounds. D) an isotope. E) a compound

C) a mixture of different compounds.

Chemically, clean [non-polluted] air is A) a compound. B) an element. C) a mixture. D) an isotope.

C) a mixture.

While a rock is falling straight down with negligible air resistance, it has A) a decreasing speed. B) zero speed. C) an increasing speed. D) an unchanging speed. E) None of the above.

C) an increasing speed.

Any rock having a very large mass would necessarily A) move very slowly. B) have a very large weight. C) be very difficult to accelerate. D) All of the above. E) need to go on a diet.

C) be very difficult to accelerate.

Tycho Braheʹs extremely accurate measurements of the planetary positions showed that A) Copernicusʹs theory was wrong and Ptolemyʹs was correct. B) both Ptolemyʹs theory and Copernicusʹs theory were correct. C) both Ptolemyʹs theory and Copernicusʹs theory were wrong. D) Ptolemyʹs theory was wrong and Copernicusʹs theory was correct. E) Keplerʹs theory was wrong.

C) both Ptolemyʹs theory and Copernicusʹs theory were wrong.

The moonʹs velocity is directed A) zero. B) inward, toward the center of Earth. C) forward, along its direction of motion. D) backward, opposite to its direction of motion. E) outward, away from Earth.

C) forward, along its direction of motion.

If a man says to you that he is absolutely certain of some idea, you can conclude that A) he is wrong. B) he is a fanatic. C) he is not being scientific. D) if his idea really is absolutely true then it must be based on scientific reasoning. E) he is right.

C) he is not being scientific.

According to the planetary model, an atom is A) made of protons, electrons, and ions. B) a single tiny object, not made of parts. C) made of protons, electrons, and neutrons. D) impossible to visualize [or picture]. E) made of protons and electrons

C) made of protons, electrons, and neutrons.

Velma, the space woman, orbiting at 100 miles above earthʹs surface, feels weightless because A) she is away from the pull of earthʹs gravity. B) she went on a diet. C) she is falling freely around Earth. D) she is in a vacuum. E) Actually, she doesnʹt feel weightless.

C) she is falling freely around Earth.

At the microscopic level, the difference between liquids and solids is that A) in a liquid, the individual atoms are larger. B) there is much more distance [at least 10 times more] between neighboring atoms in a liquid than between neighboring atoms in a solid. C) the liquidʹs atoms move throughout the liquid, while the solidʹs atoms remain near their original locations. D) both answers A and B are correct. E) both answers B and C are correct.

C) the liquidʹs atoms move throughout the liquid, while the solidʹs atoms remain near their original locations.

Compared to the gravitational force on a 1 kg object, the gravitational force on a 2 kg object is A) four times larger. B) the same. C) twice as large. D) nine times larger. E) None of the above.

C) twice as large.

An astronaut drops a rock on the moon. It falls 1 meter in 1 second. In 4 seconds, it falls a total distance of A) 12 meters. B) 4 meters. C) 9 meters. D) 16 meters. E) 8 meters.

D) 16 meters.

You push your 2 kg physics book along a tabletop, pushing it with 10 newtons of force. If the book is greased so that friction is negligible, the bookʹs acceleration is A) 20 m/s2. B) zero. C) infinitely large. D) 5 m/s2. E) 0.2 m/s2.

D) 5 m/s2.

Which of the following best describes the meaning of ʺforceʺ? A) A force is a change in velocity. B) The force that a body has is the amount of work that the body can do. C) A bodyʹs force is the tendency of that body to continue moving once it is started moving. D) A body exerts a force on another body when the first body causes the second body to accelerate. E) The force of a moving body is the distance the body travels divided by the time it takes to travel that distance.

D) A body exerts a force on another body when the first body causes the second body to accelerate.

Which of the following represents a continuation of the basic general idea of the ʺCopernican revolutionʺ? A) The idea that the human species is not very different biologically from the other species. B) The idea that our sun is just one star among billions of similar stars. C) The idea that the universe was not made just for us. D) All of the above. E) None of the above.

D) All of the above.

Suppose that the gravitational force by Earth on the moon suddenly shut off. How would the moon then move? A) It would go into a larger circular orbit. B) It would slow down and stop. C) It would move directly outward, away from Earth. D) It would move straight ahead in a straight line, at constant speed. E) It would move directly inward, toward Earth.

D) It would move straight ahead in a straight line, at constant speed.

According to Galileo, which of these is a ʺnaturalʺ or ʺunforcedʺ motion? A) A book coming to rest as it slides along the floor. B) A stone falling straight downward. C) Both of the above. D) Neither of the above.

D) Neither of the above.

The law of gravity was invented by A) Ptolemy. B) Galileo. C) Copernicus. D) Newton. E) Kepler.

D) Newton.

Suppose we could magically double the mass of the moon, double the mass of Earth, and double the distance between Earth and the moon, all at the same time. How would this affect the force that the moon exerts on Earth? A) The force would be halved. B) The force would be quadrupled. C) The force would be doubled. D) The force would be unchanged. E) The force would be multiplied by eight.

D) The force would be unchanged.

Is any force exerted on you when you slow down while moving along a straight line? A) No, no force acts as long as you are slowing down. B) Yes, there is a forward force on you, along your direction of motion. C) Yes, there is a force on you but it is impossible to state the direction of this force because the question contains insufficient information. D) Yes, there is a backward force on you, opposite to your direction of motion. E) Yes, there is a sideways force on you.

D) Yes, there is a backward force on you, opposite to your direction of motion.

If you somehow increased Earthʹs radius, without changing its mass, would this affect your weight? A) No, because the force of gravity on your body depends only on your mass and on Earthʹs total mass --it doesnʹt depend on Earthʹs size. B) No, because your weight always remains the same regardless of how you change the external surroundings. C) Yes, your weight would increase. D) Yes, your weight would decrease

D) Yes, your weight would decrease

Today, the idea that everything is made of atoms should be classified as A) a fact. B) a certainty. C) Both of the above. D) a theory. E) a hypothesis.

D) a theory.

The Greek model of the atom should be classified as A) an experimental fact. B) a useless falsehood. C) a tentative hypothesis. D) a useful theory. E) an observation.

D) a useful theory.

A ball is thrown straight upward. While it is moving upward, the ballʹs acceleration is A) in the upward direction. B) in the horizontal direction. C) zero, i.e., the ball is not accelerating. D) in the downward direction. E) None of the above.

D) in the downward direction.

What keeps Earth moving? A) Actually, it isnʹt moving. B) solar energy C) gravity D) its inertia E) the energy of space

D) its inertia

When you pull an object, such as a table, across the floor, the forward force by you on the table is equal but opposite to the backward force by the table on you. It seems as though these two forces should balance out, so that the table canʹt be moved. But the table does move, because A) the floor pushes forward on the table. B) the force by you on the table is larger than the force of the table on you. C) the momentum always acts in a forward direction. D) only one of these two forces actually acts on the table. E) Newtonʹs laws do not apply to the table considered as a separate object.

D) only one of these two forces actually acts on the table.

Which statement illustrates the fact that two different theories can both agree with the same set of observations? A) Nonsense--it is impossible for two different theories to both be correct. B) the theories of Copernicus and Kepler, after Tycho made his observations C) the theories of Galileo and Kepler D) the theories of Ptolemy and Copernicus, before Tycho made his observations E) the Earth-centered circular orbit theory of the early Greeks, and the later theory of Ptolemy

D) the theories of Ptolemy and Copernicus, before Tycho made his observations

The ancient Greeks noted that the planets A) moved in ellipses around the sun. B) were a reddish color. C) kept step with the stars. D) wandered around among the stars. E) Nonsense--the Greeks didnʹt know anything about the planets.

D) wandered around among the stars.

An individual sulfur atom has twice the weight of an individual oxygen atom. What is the weight ratio of sulfur and oxygen in the formation of sulfur dioxide? A) 1 part sulfur to 2 parts oxygen B) 2 parts sulfur to 1 part oxygen C) 1 part sulfur to 4 parts oxygen D) 4 parts sulfur to 1 part oxygen E) 1 part sulfur to 1 part oxygen

E) 1 part sulfur to 1 part oxygen

You ride a motor scooter 8 km in 15 minutes. Your [average] speed is A) 48 km/hr. B) 4 km/hr. C) 16 km/hr. D) 2 km/hr. E) 32 km/hr.

E) 32 km/hr.

The figure represents a multiple-flash photo of two balls moving to the right, and shows both balls at several numbered times. The time between flashes is 0.20 s, and the large divisions on the measuring rod are centimeters. The speed of the lower ball is A) 0.4 cm/s. B) 4.8 cm/s. C) 1.2 cm/s. D) 0.8 cm/s. E) 6 cm/s.

E) 6 cm/s.

Evidence that things are made of atoms comes from A) the observation that we can smell things such as bread from a distance. B) from the observation that, when chemicals combine to form new chemicals, they do so in simple ratios by weight. C) Both of the above answers. D) Brownian motion. E) All of the above answers.

E) All of the above answers.

What keeps the moon moving, i.e., why doesnʹt the moon slow down and stop? A) The sunʹs gravity keeps it moving. B) Nuclear processes operating in the central core of the moon. C) Earthʹs gravity keeps it moving. D) It actually is slowing down, and will come to rest in a few thousand more years. E) It is the natural motion of every object to keep moving by itself.

E) It is the natural motion of every object to keep moving by itself.

You ride a motor scooter 8 km in 10 minutes. Your speed is A) 40 km/hr. B) 16 km/hr. C) 24 km/hr. D) 32 km/hr. E) None of the above.

E) None of the above.

Kepler was finally able to absolutely prove the truth of his theory of the motion of the planets by using A) his own highly accurate observations of the planets. B) data gathered by the ancient Greeks. C) the data of Tycho Brahe. D) All of the above. E) Nonsense--it is impossible to prove that a theory is true.

E) Nonsense--it is impossible to prove that a theory is true

What other force balances the downward pull of gravity on a NASA satellite while it is in orbit around Earth? A) The acceleration. B) The velocity. C) Centrifugal force. D) A balancing force is not needed because gravity doesnʹt act on the satellite. E) There is no balancing force--gravity is the only force on the satellite.

E) There is no balancing force--gravity is the only force on the satellite.

How did Brahe measure highly accurate planetary positions? A) By his invention of the technique know as triangulation (measuring the distance between 2 points, and measuring 2 angles, to determine the distance to a 3rd point). B) With a new type of telescope that used mirrors instead of lenses. C) By careful measurements of the brightness of the planets, as seen from Earth. D) With the recently-invented telescope. E) With larger and more elegant sighting instruments.

E) With larger and more elegant sighting instruments.

Can two pool balls, both of them moving, have a total momentum of zero? A) No, because any moving object has momentum. B) No, because they both have energy. C) Yes, but only at the instant that they collide. D) Yes, if they are both moving outward from the same point. E) Yes, if they are moving in opposite directions, both with the same speed

E) Yes, if they are moving in opposite directions, both with the same speed

Chemically, helium is A) a compound. B) a mixture. C) a solid. D) an isotope. E) an element.

E) an element.

The law of inertia says that A) if there is a force on a body, the body will have no acceleration. B) if there is no force on a body, the body will have a changing velocity. C) if there is a force on a body, the body will have a changing acceleration. D) if there is a force on a body, the body will have an unchanging velocity. E) if there is no force on a body, the body will have no acceleration.

E) if there is no force on a body, the body will have no acceleration.

A 39-kg girl standing at rest on slippery (frictionless) ice catches a 1-g ball moving at 10 m/s. Just afterward, the girl is A) moving at 0.5 m/s. B) at rest. C) moving at 2 m/s. D) moving at 4 m/s. E) moving at 0.25 m/s.

E) moving at 0.25 m/s.

1) If you observe the night sky in the direction of the North Star, you will observe that A) the north star moves eastward across the sky during the night. B) the north star moves westward across the sky during the night. C) the other stars near the north star move in straight lines from east to west during the night. D) the other stars near the north star move along clockwise circles around the north star during the night. E) the other stars near the north star move along counterclockwise circles around the north star during the night.

E) the other stars near the north star move along counterclockwise circles around the north star during the night.

If you went to the moon, you would find that A) your mass would be reduced, but not your weight. B) it really is made of blue cheese. C) both your weight and your mass would be reduced. D) your weight would be increased. E) your weight would be reduced, but not your mass.

E) your weight would be reduced, but not your mass.