Deck 5: Newtons Universe

Question 1

Velma, the space woman, is orbiting above Earth's surface in a low- altitude orbit. Does she actually have weight, or is she actually weightless, and why?

A) She actually has weight, because her weight remains the same no matter where she goes in the universe.
B) She actually has weight, because Earth actually is pulling on her with nearly the normal pull of gravity.
C) She is weightless because she is falling freely around the earth.
D) She is weightless because she is away from the pull of Earth's gravity.
E) She is weightless because she is in a vacuum.

Answer 1

She actually has weight, because Earth actually is pulling on her with nearly the normal pull of gravity.

Question 2

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) Both of the above.
D) Moving the two objects farther apart.
E) None of the above.

Answer 2

Moving the two objects farther apart.

Question 3

Newton's principles of mechanics are important because

A) no exceptions have ever been found to them.
B) they tie together [or "explain"] a wide range of observed phenomena.
C) of the influential role they played in the development of science during the 14th and 15th centuries.
D) Actually they are of little importance, due to their limited range of validity.
E) Actually they are now known to be incorrect and hence are of no real scientific importance today.

Answer 3

they tie together [or "explain"] a wide range of observed phenomena.

Question 4

Mort weighs 700 newtons on Earth. He takes a low- orbit voyage in an Earth satellite. While in orbit his apparent weight [his feeling of weight] is

A) just a few newtons.
B) a little more than 700 newtons.
C) zero.
D) a little less than 700 newtons.
E) 700 newtons.

Question 5

According to Newtonian physics, and to the philosophical views usually associated with Newtonian physics, the workings of the physical universe are

A) an anti- American plot.
B) partially pre- determined and partially a matter of chance.
C) predetermined in their overall outlines, but with certain details [such as human decision- making] left to chance or to free will.
D) completely a matter of chance.
E) completely predetermined, just like the workings of a clock.

Question 6

Velma, the space woman, orbiting at 100 miles above earth's surface, feels weightless because

A) she went on a diet.
B) she is falling freely around Earth.
C) she is in a vacuum.
D) she is away from the pull of earth's gravity.
E) Actually, she doesn't feel weightless.

Question 7

Suppose Earth collapsed down to one- tenth of its present radius, while retaining all of its present mass. Compared to your present weight, your weight would then be

A) increased by a factor of 100.
B) unchanged.
C) reduced by a factor of 10.
D) increased by a factor of 10.
E) reduced by a factor of 100.

Question 8

The pulsations from a neutron star are due to

A) the nuclear reactions taking place in its center.
B) the vibrations of its neutrons.
C) its large mass.
D) its rapid spinning motion.
E) the gas that surrounds it.

Question 9

In the view of the science of the 17th, 18th, and 19th centuries, the natural world

A) is similar to a clock.
B) is not real.
C) is similar to a living organism.
D) has a sort of free will of its own.
E) cannot be investigated by scientific methods.

Question 10

Astronauts inside Earth satellites such as the space shuttle are usually said to be "in orbit" around Earth. Are you "in orbit" around anything?

A) Yes, around both Earth and the sun.
B) Yes, around the sun due to Earth's motion through space [but not around Earth].
C) Yes, around Earth due to Earth's spinning motion [but not around the sun].
D) No.
E) Only on Saturdays.

Question 11

According to current theories, how did the sun's planets get here?

A) Stars such as the sun, and planets such as those around the sun, all formed shortly after the big bang, and then gathered into "solar systems" such as we see today.
B) The sun was originally part of the two- star system, the second star split up into pieces, and these pieces developed into the planets.
C) After the sun had formed, it gathered fully- formed planets from various places as the sun moved through the galaxy.
D) A passing star tore off part of the sun, and this part separated into pieces to form the planets.
E) 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.

Question 12

How did Newton deduce the dependence of the gravitational force on distance?

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

Question 13

What is the present scientific status of Newtonian physics?

A) We now know that Newtonian physics is correct.
B) Although we cannot know for certain that Newtonian physics is correct, no violations have ever been discovered.
C) Newtonian physics is now known to be wrong and thus it is no longer useful in science.
D) Newtonian physics does not apply to very small objects, but otherwise no violations have been discovered.
E) Newtonian physics does not apply to very small objects, high- speed objects, and very strong gravitational forces.

Question 14

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) directed horizontally forward.
B) directed upward.
C) directed horizontally backward.
D) zero.
E) directed downward.

Question 15

A common belief is that everything that happens is predetermined by the predetermined mechanical motions of atoms, much as a clock operates. A good argument against this position is

A) many great scientists, such as Democritus, Kepler, and Newton, dispute this belief.
B) science is not really relevant to our lives anyway.
C) Newtonian physics, on which this idea is based, cannot be conclusively proven to be true.
D) All of the above are good answers.
E) Actually, there isn't any good answer to this position.

Question 16

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 forward, along its direction of motion.
D) Yes, its acceleration is directed outward away from Earth.
E) Yes, its acceleration is directed inward toward Earth.

Question 17

The similarity that Newton recognized between a falling apple and the moon was

A) both have an acceleration that is directed toward the center of Earth.
B) the force on both is directed toward Earth's center.
C) Both of the above.
D) Actually there is no important similarity between these two.
E) None of the above.

Question 18

Astronauts in orbit around Earth feel weightless because

A) there is no gravity out there.
B) they must lose weight for the space program.
C) they are in "free fall" around Earth.
D) no forces at all are acting on them.
E) they are moving with constant velocity.

Question 19

Suppose we could magically triple the distance between Earth and the moon. This would cause the gravitational force by Earth on the moon to be

A) reduced to 1/9 of its former value.
B) reduced to 1/4 of its former value.
C) increased to three times its former value.
D) be unchanged.
E) reduced to 1/3 of its former value.

Question 20

The cause of the pulsations we see in the light from neutron stars is

A) pulsations of its neutrons.
B) motions of electrons within the star.
C) the spinning motion of the star.
D) the in and out pulsations of star's radius, as the star gets rapidly larger and then smaller.
E) Nonsense-- neutron stars do not pulsate.

Question 21

Are you in orbit around anything?

A) No, because you are at rest relative to space.
B) No, because you are at rest relative to Earth's surface.
C) Yes, you are in orbit around the sun.
D) Yes, you are in orbit both around the sun and around Earth's center.
E) Yes, you are in orbit around Earth's center.

Question 22

In the final phases of its "life", our sun will

A) collapse and continue to collapse, forever.
B) collapse to become a white dwarf.
C) turn into a cockroach.
D) blow up in a supernova explosion.
E) pass through the white dwarf state, then the neutron star state, and finally the black hole state.

Question 23

Compared to the gravitational force on a 1 kg object, the gravitational force on a 2 kg object is

A) the same.
B) twice as large.
C) nine times larger.
D) four times larger.
E) None of the above.

Question 24

Suppose that the gravitational force by Earth on the moon suddenly shut off. How would the moon then move?

A) It would move directly outward, away from Earth.
B) It would move straight ahead in a straight line, at constant speed.
C) It would slow down and stop.
D) It would go into a larger circular orbit.
E) It would move directly inward, toward Earth.

Question 25

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) stars near the center of our galaxy that are being pulled inward and disappearing due to a very massive but small object in the center.
C) stars near the center of our galaxy that are moving so fast that they must be held in orbit by a massive black hole.
D) observations of certain regions of space, larger than the largest known stars, but that emit no light.
E) X-rays that are thought to come from the center of a black hole.

Question 26

Jill's weight is 500 newtons. If Earth gravitationally collapses from its present radius of 6000 km down to a radius of only 600 km, Jill's weight would then be

A) 5000 newtons.
B) unchanged.
C) 2000 newtons.
D) 50,000 newtons.
E) 5 newtons.

Question 27

What other force balances the downward pull of gravity on a NASA satellite while it is in orbit around Earth?

A) The velocity.
B) The acceleration.
C) Centrifugal force.
D) A balancing force is not needed because gravity doesn't act on the satellite.
E) There is no balancing force-- gravity is the only force on the satellite.

Question 28

The acceleration of the moon is

A) directed toward Earth
B) directed outward away from earth
C) zero.
D) directed along its forward direction of motion
E) None of the above.

Question 29

Suppose that Earth suddenly collapsed to one- fourth of its present radius. Compared to your present weight, your weight would then be

A) 16 times smaller.
B) 4 times larger.
C) 16 times larger.
D) 8 times larger.
E) unchanged.

Question 30

The law of gravity was invented by

A) Galileo.
B) Kepler.
C) Ptolemy.
D) Copernicus.
E) Newton.

Question 31

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 multiplied by eight.
B) The force would be doubled.
C) The force would be quadrupled.
D) The force would be unchanged.
E) The force would be halved.

Question 32

If gold were always sold by weight, could you make money buying gold at one altitude above the ground and selling it at a different altitude?

A) Yes, you could make money by buying gold at a lower altitude and selling it at a higher altitude.
B) Yes, you could make money by buying gold at a higher altitude and selling it at a lower altitude.
C) Yes, you could make money by buying it at either a lower or higher altitude, and then selling it at the other altitude.
D) No, you couldn't make any money this way because the mass of the gold would be the same at both altitudes.
E) No, you couldn't make any money this way because the weight of the gold would be the same at both altitudes.

Question 33

Newtonian physics, coupled to the idea that everything is made of atoms, has led many scientists and philosophers to the conclusion that everything in the universe, including all human actions and human feelings, is pre- determined by the laws of physics and acts just like a machine. Which of the following statements is a scientifically- acceptable reason for disagreeing with this conclusion?

A) Isaac Newton himself believed that humans have free will.
B) We should never accept scientific theories as absolute truth.
C) Both of the above.
D) Our own intuitions, or beliefs, inform us that we actually do have free will.
E) None of the above.

Question 34

Suppose Earth collapsed down to one- hundredth [1/100] of its present radius. How would this affect your weight? Your weight would be

A) increased by a factor of 100.
B) unchanged.
C) increased by a factor of 10,000.
D) reduced by a factor of 100.
E) increased by a factor of 1000.

Question 35

Why is Isaac Newton sometimes said to have "united the heavens and Earth"?

A) Because of the fact that there are no exceptions to the laws of thermodynamics.
B) Because Newton's law of gravity seems to apply throughout the universe.
C) Because Newton's law of conservation of energy seems to apply throughout the universe.
D) Because he discovered that the energy processes that power the sun also operate on Earth.
E) Because he caused the scientific community to accept the idea that Earth is just one planet orbiting the sun like the other planets.

Question 36

An astronaut's 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) 300 newtons
D) 200 newtons
E) 150 newtons

Question 37

A white dwarf star is about the size of

A) Earth.
B) a highway truck.
C) the head of a pin.
D) the sun.
E) Actually, it doesn't have any size at all.

Question 38

Is there any actual evidence that our solar system originate from a collapsing cloud of gas, as described in the textbook?

A) Evidence comes from observations of the moon, meteorites, other planets, and other moons.
B) Evidence comes from observations of gas clouds around new stars elsewhere in our galaxy.
C) Evidence comes from observations of Earth's oldest rocks.
D) All of the above.
E) No, this description is based only on the theory of gravity and other theories.

Question 39

There are three types of collapsed, burned- out stars: black holes, white dwarfs, and

A) supernova.
B) red giants.
C) X-ray stars.
D) neutron stars.
E) quasars.

Question 40

The moon's acceleration is directed

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

Question 41

Which of the following has the effect of reducing the gravitational force between two objects?

A) Moving the two objects closer together.
B) Moving the two objects farther apart.
C) Increasing the mass of either one of the objects.
D) None of these.

Question 42

The figure shows the moon orbiting around Earth. Suppose that the force of gravity between Earth and moon suddenly "switched off." Which of the three arrows point in the direction that the moon would move after gravity vanished?

A) arrow A
B) arrow B
C) arrow C
D) None of them, because the moon's velocity would be zero if the gravitational force vanished.
E) None of them, because the correct direction is a combination of two of the directions shown in the diagram.

Question 43

As the moon circles Earth, the net force on it is

A) zero.
B) backward.
C) forward.
D) directed outward away from Earth.
E) directed inward toward Earth.

Question 44

Our sun will conclude its life as

A) a white dwarf.
B) a daffodil.
C) a black hole.
D) a neutron star.
E) a red giant.

Question 45

NASA satellites stay up because

A) they are away from Earth's gravity and thus do not get pulled down toward Earth.
B) they are moving so fast that they are able to "fall" around Earth.
C) there is no air resistance in outer space and thus no downward force on an orbiting satellite.
D) centrifugal force pulls outward on them.
E) their rocket engines hold them above Earth's surface.

Question 46

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.

Question 47

A philosopher informs you that you do not have any free will, because Newtonian physics predicts that the physical universe and everything in it behaves in a deterministic fashion, just like the workings of a clock. A good argument against this position is that

A) it is impossible to scientifically prove such a general statement.
B) Newtonian physics is now known to be incorrect in certain situations.
C) Both of the above.
D) None of the above.
E) all philosophers are knaves and fools.

Question 48

Suppose that the force of gravity between the sun and Earth suddenly stopped operating. What would happen?

A) Earth would move straight ahead, in a straight line, rather than orbiting the sun.
B) Earth would continue orbiting the sun, but objects on Earth would have no weight and would float into space.
C) Earth would fall directly inward, into the sun.
D) Earth would stop in its orbit around the sun, and remain motionless at its present position.
E) Earth would fly directly outward from the sun.

Question 49

Which of the following would increase the gravitational force between two objects?

A) Reducing the mass of either one of the objects.
B) Moving the two objects farther apart.
C) Moving the two objects closer together.
D) None of these.

Question 50

The figure shows the moon orbiting around Earth. Suppose that the direction of the moon's 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.

Question 51

Which one [or ones] of the following is a possible final state for a star that has come to the end of its "lifetime" by running out of fuel and then gravitationally collapsing?

A) black hole
B) white dwarf
C) neutron star
D) All of the above.
E) None of the above.

Question 52

Suppose Earth collapsed down to one- tenth of its present radius, while retaining all of its present mass. Compared to your present mass, your mass would be

A) increased by a factor of 100.
B) reduced by a factor of 10.
C) increased by a factor of 10.
D) reduced by a factor of 100.
E) unchanged.

Question 53

Astronauts, in satellites orbiting Earth, feel weightless. Are they really weightless?

A) Yes, because the centrifugal force due to their circular motion balances the force of gravity.
B) Yes, because they are not in Earth's gravitational field.
C) Yes, because they are "falling" around Earth.
D) No, because the gravitational force is pulling downward on them.
E) No, because the centrifugal force is pulling outward on them.

Question 54

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.

Question 55

If you weighed 800 newtons on Earth, how much would you weigh at 6000 km [one Earth radius] above the surface of Earth?

A) 1600 newtons
B) 3200 newtons
C) 200 newtons
D) 400 newtons
E) 800 newtons

Question 56

A space satellite weighs 100,000 newtons on Earth. When orbiting at a height of 6000 km [one Earth- radius] above Earth, its weight is

A) zero.
B) 400,000 newtons.
C) 25,000 newtons.
D) 100,000 newtons.
E) 50,000 newtons.

Question 57

Today, we know that Newton's "laws" are

A) in agreement with all known experimental evidence.
B) incapable of explaining the motions of the planets.
C) often incorrect when applied to liquids.
D) often incorrect when applied to molecular- sized objects.
E) no longer useful as scientific principles.

Question 58

We now know that Newtonian physics is not valid [i.e., not correct] for

A) gases.
B) very fast- moving objects.
C) solid objects.
D) stationary objects.
E) Nonsense-- Newtonian physics has never been found to be incorrect.

Question 59

You hold an apple in one hand and an orange in the other. If you doubled the mass of the apple and tripled the mass of the orange, without changing the distance between them, the gravitational force between them would be

A) unchanged, because it is zero both before and after the mass alterations.
B) five times larger.
C) six times larger.
D) three times larger.
E) doubled.

Question 60

If you somehow increased Earth's radius, without changing its mass, would this affect your weight?

A) Yes, your weight would decrease.
B) No, because your weight always remains the same regardless of how you change the external surroundings.
C) Yes, your weight would increase.
D) No, because the force of gravity on your body depends only on your mass and on Earth's total mass-- it doesn't depend on Earth's size.

Question 61

You hold an apple in one hand and an orange in the other. If you doubled the mass of the apple and tripled the mass of the orange, without changing the distance between them, the weight of the orange [on Earth] would be

A) doubled.
B) unchanged.
C) six times larger.
D) tripled.
E) five times larger.

Question 62

Is there a force on the moon, and how do you know?

A) No, because the moon moves at an unchanging speed.
B) No, because the moon is not accelerated.
C) Yes, because there must be a force pulling outward on the moon, away from Earth, to keep the moon from falling down to Earth.
D) Yes, because the moon is accelerated.
E) Yes, because there must be a force to keep the moon moving.

Question 63

There are three types of collapsed, burned- out stars: black holes, neutron stars, and

A) X-ray stars.
B) supernova.
C) red giants.
D) quasars.
E) white dwarfs.

Question 64

What originally caused the sun to heat up?

A) Nuclear fusion reactions that occurred during the time when the sun's gases were spread out and beginning to fall together by gravitational attraction.
B) The gases from which it formed had already been heated by the Big Bang.
C) As the sun's gases gathered together by their own gravity, they accelerated inward and collided.
D) Electromagnetic radiation from outside the sun heated the sun's gases as they gathered together.
E) A nearby supernova explosion that occurred during the early stages of the formation of the sun.

Question 65

What similarity did Isaac Newton perceive between a falling apple and the moon?

A) The velocities of both are directed toward Earth's center.
B) Both have a velocities and accelerations directed toward Earth's center.
C) Both have accelerations directed toward Earth's center, although the forces on them are in different directions.
D) Both have forces on them toward Earth's center, and accelerations directed toward Earth's center.
E) Both have forces on them toward Earth's center, but their accelerations are in different directions.

Question 66

During this century, we have found that Newton's physics does not apply to

A) very small objects.
B) very strong gravitational forces.
C) high speed objects.
D) All of the above.
E) Nonsense-- Newton's physics always applies.

Question 67

The important similarity that Newton noticed between a falling apple and the moon was that

A) both are moving.
B) both are good to eat.
C) the accelerations of both are toward Earth's center.
D) the velocities of both are toward Earth's center.
E) the net force on both is away from Earth, i.e., outward from the center of Earth.

Question 68

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) X-rays that are thought to come from the center of a black hole.
C) temperature measurement of certain extremely cold stars that are thought to be black holes.
D) X-rays that are thought to come from gases that are outside of a black hole.
E) observations of certain regions of space, larger than the largest known stars, that emit no light.

Question 69

How strongly, and in what direction, does a 1- newton apple pull on Earth?

A) The apple does not pull on Earth at all; it is Earth that pulls downward on the apple.
B) It pulls upward, with a force that is much smaller than 1 newton.
C) It pulls downward, with a force of 1 newton.
D) It pulls upward, with a force of 1 newton.
E) It pulls upward, with a force that is much larger than 1 newton.

Question 70

The moon's velocity is directed

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

Question 71

Mort weighs 700 newtons on Earth. He takes a low- orbit voyage in an Earth satellite. During the voyage his weight is

A) zero.
B) just a few newtons.
C) a little less than 700 newtons.
D) 700 newtons.
E) a little more than 700 newtons.

Question 72

Where did Earth come from?

A) The Big Bang compressed matter into stars and planets such as Earth.
B) A passing star tore off part of the sun, and this part developed into Earth.
C) Earth was originally one of Jupiter's moons.
D) From gases gathered by the sun after the sun had already formed.
E) From the same collapsing gas cloud that gathered together to form the sun.

Question 73

Imagine that you could magically move the moon closer to Earth, so that the distance from Earth to moon is cut in half. This would cause the force that Earth exerts on the moon to be

A) increased to four times its original value.
B) doubled.
C) reduced to 1/4 of its original value.
D) halved.
E) Nonsense-- Earth exerts no force on the moon.

Question 74

Does Earth's gravity pull more strongly on a block of wood or on a block or iron having the same size? Neglecting air resistance, which one falls faster when dropped?

A) Gravity pulls more strongly on the iron, and the iron falls faster.
B) Gravity pulls more strongly on the iron, and both fall at the same speed.
C) Gravity pulls equally strongly on both, and the iron falls faster.
D) Gravity pulls equally strongly on both, and both fall at the same speed.
E) None of the above.

Question 75

How is the gravitational force between two objects affected by changes in the masses of the objects and by changes in the distance between the two objects?

A) The force decreases with increased mass, and decreases with increased distance.
B) The force decreases with increased mass, and increases with increased distance.
C) The force increases with increased mass, and decreases with increased distance.
D) The force increases with increased mass, and increases with increased distance.

Question 76

Which of the following statements best describes the limitations of Newtonian physics?

A) As far as we know, Newtonian physics is correct in all situations.
B) At high speeds, or at small sizes, or for large distances, Newtonian physics is incorrect.
C) At very high speeds, or at very small sizes, or for gases and liquids, Newtonian physics gives very incorrect predictions.
D) At very high speeds, Newtonian physics gives very incorrect predictions, and is correct in other situations.
E) Newtonian physics is approximately correct, to within 1 or 2 percent, in all situations.

Question 77

The figure shows the moon orbiting around Earth. Suppose that the direction of the moon's motion is counterclockwise. Which of the arrows points in the direction of the moon's acceleration?

A) arrow A
B) arrow B
C) arrow C
D) None of them, because the moon's acceleration is zero.
E) None of them, because the correct direction is a combination of two of the directions shown in the diagram.

Question 78

There are three types of collapsed, burned- out stars: white dwarfs, neutron stars, and

A) red giants.
B) black holes.
C) X-ray stars.
D) quasars.
E) supernova.

Question 79

The least massive stars, including our sun, eventually end their lives as

A) black holes.
B) quasars.
C) neutron stars.
D) white dwarfs.
E) red giants.