Deck 4: Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Question 1

Which statement must be true in order for a rocket to travel from Earth to another planet?

A)It must be launched from space, rather than from the ground.
B)It must have very large engines.
C)It must attain escape velocity from Earth.
D)It must carry a lot of extra fuel.

Answer 1

C

Question 2

What is the acceleration of gravity at the surface of Earth?

A)9)8 km/s2 downward
B)9)8 km/s downward
C)9)8 m2/s downward
D)9)8 m/s2 downward
E)9)8 m/s downward

Answer 2

D

Question 3

Suppose you heat an oven to 400°F and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?

A)The water can transfer heat to your arm more quickly than the air.
B)The molecules in the water are moving faster than the molecules in the oven.
C)The oven has a higher temperature than the water.
D)The water has a higher temperature than the oven.

Answer 3

A

Question 4

The ultimate source of energy that powers the Sun is

A)chemical potential energy of hydrogen burning into helium.
B)thermal energy of the hydrogen atoms in the Sun.
C)mass energy of hydrogen fusing into helium.
D)kinetic energy of the orbital motion of the Sun.
E)gravitational potential energy of the contraction of the gas cloud that formed the Sun.

Question 5

Momentum is defined as .

A)force times velocity
B)mass times speed
C)mass times acceleration
D)mass times velocity

Question 6

Newton's version of Kepler's third law states According to this, what observational information does one need in order to calculate the combined mass of a planet and its moon?

A)the orbital period and the density of the two objects
B)the radius of the two planets in meters and the average distance between them
C)the average distance between the two objects and the orbital period
D)It is impossible to determine the mass of any astronomical object.

Question 7

Approximately where is it currently high tide on Earth?

A)wherever it is currently noon
B)only on the portion of the Earth facing directly toward the Moon
C)on the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon
D)anywhere that ocean water laps upon the shore

Question 8

Newton's second law states: sum of forces = mass × acceleration. According to this, what property can you determine if you observe the acceleration of an object with a known mass?

A)the sum total of all forces acting on the object
B)the current velocity of the object.
C)the value of a single force acting on the object
D)the current location of the object

Question 9

The difference between speed and velocity is that _ _.

A)velocity is calculated using a physics equation
B)velocity also includes a direction
C)velocity is the same as acceleration but speed is different
D)they are expressed in different units

Question 10

According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them .

A)increases by a factor of 3
B)decreases by a factor of 9
C)increases by a factor of 9
D)decreases by a factor of 3

Question 11

The gravitational force that the Earth exerts on the Moon is equal and opposite to that which the Moon exerts on the Earth. Therefore, according to Newton's second law of motion,

A)the Moon and the Earth both have equal accelerations, because the forces are equal.
B)the Earth has a larger acceleration than the Moon, because it has a larger mass.
C)the Moon has a larger acceleration than the Earth, because it has a smaller mass.

Question 12

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the distance between two objects increases, what happens to the gravitational force between them?

A)The force increases.
B)The force decreases.
C)The force drops instantly to zero.
D)The gravitational force is not affected by distance.

Question 13

Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit (well above Jupiter's atmosphere and far from all of Jupiter's moons.)Which of the following statements would be true?

A)Jupiter's gravity would capture the asteroid, making it a new moon of Jupiter.
B)Jupiter's gravity would suck in the asteroid, causing it to crash into Jupiter.
C)The asteroid's orbit around Jupiter would not change, and it would go out on the same unbound orbit that it came in on.
D)There is no way to predict what would happen.

Question 14

The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that .

A)the planets are always accelerating
B)the planets have angular momentum
C)the planets will eventually fall into the Sun
D)a force is acting on the planets

Question 15

In which of the following cases would you feel weightless?

A)while falling from a roof
B)while accelerating downward in an elevator
C)while walking on the Moon
D)while parachuting from an airplane

Question 16

Why is Newton's version of Kepler's third law so useful to astronomers?

A)It tells us that more- distant planets orbit the Sun more slowly.
B)It allows us to calculate distances to distant objects.
C)It explains why objects spin faster when they shrink in size.
D)It can be used to determine the masses of many distant objects.

Question 17

What do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite)?

A)Orbital energy is the sum of the object's kinetic energy and its gravitational potential energy as it moves through its orbit.
B)Orbital energy is the object's kinetic energy as it moves through its orbit.
C)Orbital energy is the amount of energy required for the object to leave orbit and escape into space.
D)Orbital energy is a measure of the object's speed as it moves through its orbit.

Question 18

Why are astronauts weightless in the Space Station?

A)because the Space Station is constantly in free- fall around the Earth
B)because the Space Station is moving at constant velocity
C)because the Space Station is traveling so fast
D)because there is no gravity in space

Question 19

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does d represent?

A)the density of the smaller object
B)the universal gravitational constant
C)the distance between the two objects

Question 20

Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?

A)The ball's gravitational potential energy is greatest at the instant the ball leaves your foot.
B)The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point.
C)The ball's gravitational potential energy is greatest at the instant it returns to hit the ground.
D)The ball's gravitational potential energy is always the same.

Question 21

0 degrees Kelvin is

A)the temperature at which all random particle motion stops.
B)the temperature at which all particles move at the speed of light.
C)meaningless, a temperature outside the range defined for the Kelvin scale.
D)the temperature at which all particles transform into light.

Question 22

Newton's second law states: sum of forces = mass × acceleration. If a known force was applied to an object with a known mass, how would you predict that object's acceleration?

A)acceleration = sum of forces / mass
B)acceleration = mass / sum of forces
C)acceleration = mass × sum of forces
D)Newton's second law is irrelevant for solving this problem.

Question 23

Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun?

A)The mass of Earth is 6 × 1024 kg and Earth orbits the Sun in one year.
B)Earth is 150 million km from the Sun and orbits the Sun in one year.
C)Earth rotates in one day and orbits the Sun in one year.
D)Mercury is 0.387 AU from the Sun and Earth is 1 AU from the Sun.

Question 24

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the mass of the second object were greater, what happens to the gravitational force between them?

A)The force increases.
B)The force decreases.
C)The force drops instantly to zero.
D)The gravitational force is not affected by the mass of the second object.

Question 25

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does M1 represent?

A)the distance, in meters, between the two objects
B)the diameter, in meters, of one of the objects
C)the mass of one of the objects

Question 26

A rock held above the ground has potential energy. As the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?

A)The energy goes to producing sound and to heating the ground, rock, and surrounding air.
B)It is transformed back into gravitational potential energy.
C)The rock keeps the energy inside it in the form of mass- energy.
D)The energy goes into the ground, and as a result, the orbit of the Earth about the Sun is slightly changed.

Question 27

Considering Einstein's famous equation, E = mc2, which of the following statements is true?

A)A small amount of mass can be turned into a large amount of energy.
B)You can make mass into energy if you can accelerate the mass to the speed of light.
C)One kilogram of mass represents 1 joule of energy.
D)Mass can be turned into energy, but energy cannot be turned back into mass.
E)It takes a large amount of mass to produce a small amount of energy.

Question 28

When a spinning ice skater pulls in his arms, he spins faster because .

A)there exists an unbalanced reaction force
B)there is less friction with the ice
C)there is less friction with the air
D)his angular momentum must be conserved, so reducing his radius must increase his speed of rotation

Question 29

As an interstellar cloud of hydrogen gas shrinks in size, its temperature increases

A)because gravitational potential energy is converted to thermal energy.
B)because thermal energy is converted to radiative energy.
C)because kinetic energy is converted to radiative energy.

Question 30

Consider the elliptical orbit of a comet around the Sun. Where in its orbit does it have the largest amount of total orbital energy?

A)when it is closest to the Sun
B)when it is farthest from the Sun
C)It always has the same total orbital energy.

Question 31

If a gas cloud shrinks, its gravitational potential energy is converted into

A)chemical energy.
B)thermal energy and radiative energy.
C)kinetic energy and sound waves.
D)only radiative energy.

Question 32

If I drop a golf ball and a bowling ball simultaneously from same height above the ground, what will happen? Neglect the effects of wind or air resistance.

A)The golf ball will hit the ground before the bowling ball.
B)The golf ball and the bowling ball will hit the ground at the same time.
C)The bowling ball will hit the ground before the golf ball.

Question 33

The fact that Voyager 10 continues to speed out of the solar system, even though its rockets have no fuel, is an example of

A)Newton's first law of motion.
B)Newton's second law of motion.
C)Newton's third law of motion.
D)the universal law of gravitation.
E)none of the above

Question 34

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E = mc2?

A)A mass raised to a great height has a lot of gravitational potential energy.
B)An object accelerated to a great speed has a lot of kinetic energy.
C)A burning piece of wood produces light and heat, therefore giving off radiative and thermal energy.
D)A small amount of the hydrogen in a nuclear bomb becomes energy as fusion converts the hydrogen to helium.

Question 35

Newton's Second Law of Motion tells us that the net force applied to an object equals its _ .

A)mass times acceleration
B)mass times velocity
C)mass times energy
D)momentum times velocity

Question 36

Imagine a Star Wars type spaceship in orbit around a planet. Its engine suffers a severe malfunction, and explodes. What is the most physically realistic depiction of this event?

A)The spacecraft breaks apart, and the pieces continue to orbit the planet.
B)The spacecraft burns up in a giant fireball.
C)The spacecraft breaks in half and begins to sink down into the planet, like a sinking aircraft carrier.

Question 37

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?

A)It is less.
B)You are weightless.
C)It is the same.
D)It is greater.

Question 38

The astronauts feel weightless in the International Space Station, which orbits the Earth once every 90 minutes. Why?

A)because there is no gravity in space
B)because they and the space station are both falling around the Earth
C)because the gravity from the Moon cancels out the gravity from Earth
D)because they are moving so fast

Question 39

Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth?

A)Earth's orbit would be unaffected.
B)Earth's orbit would expand, and it would take more than one year to orbit the Sun.
C)Earth would change from a bound orbit to an unbound orbit and fly off into interstellar space.
D)The size of Earth's orbit would shrink, and it would take less than one year to orbit the Sun.

Question 40

Newton's version of Kepler's third law states: In this equation, what do M1 and M2 represent?

A)the orbital period
B)the average distance between the two objects
C)the masses of the two objects
D)the universal gravitational constant

Question 41

Imagine another solar system, with a star of the same mass as the Sun. Suppose a planet with a mass twice that of Earth (2MEarth)orbits at a distance of 1 AU from the star. What is the orbital period of this planet?

A)1 year
B)2 years
C)6 months
D)It cannot be determined from the information given.

Question 42

Newton's version of Kepler's third law states: In this equation, what does G represent?

A)the orbital period
B)the average distance between the two objects
C)the masses of the two objects
D)the universal gravitational constant

Question 43

At which lunar phase(s)are tides most pronounced (for example, the highest high tides)?

A)full moon only
B)both new and full moons
C)both first and third quarters
D)new moon only

Question 44

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does G represent?

A)the density of the smaller object
B)the universal gravitational constant
C)the distance between the two objects

Question 45

If your mass is 60 kg on Earth, what would your mass be on the Moon?

A)10 lb
B)60 kg
C)10 kg
D)60 lb
E)50 kg

Question 46

In the formula E = mc2, what does E represent?

A)the kinetic energy of a moving object
B)the mass- energy, or potential energy stored in an object's mass
C)the electric field produced by a charge
D)the radiative energy carried by light
E)the gravitational potential energy of an object held above the ground

Question 47

Suppose that two objects collide. Which of the following things is not the same both before and after the collision?

A)the total temperature of the objects
B)the total angular momentum of the objects
C)the total momentum of the objects
D)the total energy of the objects

Question 48

When space probe Voyager 2 passed by Saturn, its speed increased (but not due to firing its engines). What must have happened?

A)Saturn must have captured an asteroid at precisely the moment that Voyager 2 passed by.
B)Saturn's rotation must have sped up slightly.
C)Saturn must have lost a very tiny bit of its orbital energy.
D)Voyager 2 must have dipped through Saturn's atmosphere.

Question 49

The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds?

A)20 m/s
B)10 m/s
C)10 m/s2
D)30 m/s
E)30 m/s2

Question 50

The speed at which a pool ball moves after being struck by a cue is most directly an example of

A)Newton's first law of motion.
B)Newton's second law of motion.
C)Newton's third law of motion.
D)the universal law of gravitation.

Question 51

A net force acting on an object will always cause a change in the object's _.

A)mass
B)speed
C)momentum
D)direction

Question 52

The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them

A)strengthens by a factor of 4.
B)weakens by a factor of 2.
C)is unaffected.
D)weakens by a factor of 4.
E)also doubles.

Question 53

Suppose you drop a 10- pound weight and a 5- pound weight on the Moon, both from the same height at the same time. What will happen?

A)Both weights will float freely, since everything is weightless on the Moon.
B)Both will hit the ground at the same time.
C)The 10- pound weight will hit the ground before the 5- pound weight.
D)The 5- pound weight will hit the ground before the 10- pound weight.

Question 54

Absolute zero is .

A)100° Celsius
B)0 Kelvin
C)0° Fahrenheit
D)0° Celsius

Question 55

Which of the following represents a case in which you are not accelerating?

A)driving 60 miles per hour around a curve
B)going from 0 to 60 miles per hour in 10 seconds
C)driving in a straight line at 60 miles per hour
D)slamming on the brakes to come to a stop at a stop sign

Question 56

You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?

A)The elevator is accelerating downwards.
B)The elevator is moving at a constant velocity upwards.
C)The elevator is accelerating upwards.
D)The elevator is moving at a constant velocity downwards.
E)Your diet is working.

Question 57

According to the universal law of gravitation, the force due to gravity is

A)directly proportional to the distance between objects.
B)not dependent on the distance between objects.
C)inversely proportional to the square of the distance between objects.
D)inversely proportional to the distance between objects.
E)directly proportional to the square of the distance between objects.

Question 58

Which of the following statements correctly describes the law of conservation of energy?

A)An object always has the same amount of energy.
B)The total quantity of energy in the universe never changes.
C)Energy can change between many different forms, such as potential, kinetic, and thermal, but it is ultimately destroyed.
D)It is not really possible for an object to gain or lose potential energy because energy cannot be destroyed.
E)The fact that you can fuse hydrogen into helium to produce energy means that helium can be turned into hydrogen to produce energy.

Question 59

What is the difference between a bound orbit and an unbound orbit around the Sun?

A)An object on a bound orbit has a gravitational attraction to the Sun, while an object on an unbound orbit does not.
B)A bound orbit is an orbit allowed by the universal law of gravitation, and an unbound orbit is not.
C)A bound orbit is circular, while an unbound orbit is elliptical.
D)An object on a bound orbit follows the same path around the Sun over and over, while an object on an unbound orbit approaches the Sun just once and then never returns.

Question 60

Radiative energy is .

A)energy of motion
B)energy from nuclear power plants
C)energy carried by light
D)heat energy

Question 61

Consider the elliptical orbit of a comet around the Sun. Where in its orbit is the comet moving the fastest?

A)when it is closest to the Sun
B)when it is farthest from the Sun
C)It is always moving at the same speed.

Question 62

At which lunar phase(s)are tides least pronounced (e.g., the lowest high tides)?

A)full moon
B)first quarter
C)new moon
D)both new and full moons
E)both first and third quarters

Question 63

What quantities does angular momentum depend upon?

A)force and radius
B)mass and velocity
C)mass, velocity, and radius
D)force, velocity, and radius
E)momentum and angular velocity

Question 64

The mass of Jupiter can be calculated by

A)measuring the orbital period and distance of one of Jupiter's moons.
B)knowing the Sun's mass and measuring how Jupiter's speed changes during its elliptical orbit around the Sun.
C)measuring the orbital period and distance of Jupiter's orbit around the Sun.
D)knowing the Sun's mass and measuring the average distance of Jupiter from the Sun.
E)measuring the orbital speed of one of Jupiter's moons.

Question 65

What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?

A)It would orbit Earth at a faster velocity.
B)It would travel in a higher orbit around Earth.
C)It would take less time to reach its bound orbit.
D)It would be in an unstable orbit.
E)It would travel away from Earth into the solar system.

Question 66

Newton's version of Kepler's third law states: In this equation, what does p represent?

A)the orbital period
B)the average distance between the two objects
C)the masses of the two objects
D)the universal gravitational constant

Question 67

The amount of gravitational potential energy released as an object falls depends on

A)the distance it falls.
B)its speed at the time it begins falling.
C)neither the distance it falls nor its speed at the time it begins falling.
D)the distance it falls and its speed at the time it begins falling.

Question 68

How does the Space Shuttle take off?

A)by achieving lift from its wings in the same way that airplanes do
B)by converting mass- energy to kinetic energy
C)Its rocket engines push against the launch pad, propelling the shuttle upwards.
D)Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction.
E)The hot rocket exhaust expands the air beneath the shuttle, propelling it forward.

Question 69

Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen?

A)The Sun's rate of rotation would slow.
B)The Sun's angular size in our sky would stay the same.
C)The Sun would rotate faster than it does now.
D)This could never happen, because it is impossible for an object to shrink in size without an outside torque.

Question 70

As an interstellar cloud of hydrogen gas shrinks in size, its rate of rotation

A)increases, because the force of gravity strengthens as the cloud shrinks.
B)decreases, because its angular momentum is conserved.
C)increases, because its angular momentum is conserved.
D)decreases, because the force of gravity strengthens as the cloud shrinks.
E)increases, because its total energy is conserved.

Question 71

Newton's version of Kepler's third law states : Solve this equation to find the combined mass of a planet and its satellite, given the orbital period and average separation.

A)M1 + M2 = 4n2 × a3
B)M1 + M2 = G × p2
G p2
4n2 a3
C)M1 + M2 = G × a3
D)M1 + M2 = 4Gu2 × a3
4n2 p2 p2

Question 72

Which of the following best explains why the Moon's orbital period and rotation period are the same?

A)The law of conservation of angular momentum ensured that the Moon must have the same amount of rotational angular momentum as it has of orbital angular momentum.
B)The equality of the Moon's orbital and rotation periods is an extraordinary astronomical coincidence.
C)The Moon was once closer to Earth, but the force of gravity got weaker as the Moon moved farther away.
D)The Moon once rotated faster, but tidal friction slowed the rotation period until it matched the orbital period.

Question 73

A planet is orbiting a star. Which of the following statements is true for the acceleration and gravitational forces experienced by the star and the planet?

A)The force on the star is much smaller than the force on the planet, but the accelerations are about equal.
B)The acceleration of the planet is much more than the acceleration of the star, but the force on the star is the same but opposite the force on the planet.
C)The acceleration of the planet is much more than the acceleration of the star, and the force on the planet is much more than the force on the star.

Question 74

Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will

A)continue to move in a straight line forever if it is in space, but fall to the ground if it is on Earth.
B)continue to move in the same way until it is acted upon by a force.
C)continue to move in the same way forever, no matter what happens.
D)eventually slow down and come to a stop.

Question 75

Newton's version of Kepler's third law states: In this equation, what does a represent?

A)the orbital period
B)the average distance between the two objects
C)the masses of the two objects
D)the universal gravitational constant

Question 76

Where does the energy come from that your body uses to keep you alive?

A)It comes from the water you drink.
B)It comes from the foods you eat.
C)It is in the air that you breathe.
D)It is created during the time that you rest or sleep.
E)It is produced from the radiative energy of the Sun on your skin.

Question 77

What does temperature measure?

A)the total potential energy of particles in a substance
B)the average kinetic energy of particles in a substance
C)the average mass of particles in a substance
D)the total amount of heat in a substance

Question 78

According to what we now know from Newton's laws, which of the following best explains why Kepler's second law is true?

A)A planet's total orbital energy must be conserved as it moves around its orbit.
B)Gravity is an inverse cube law.
C)This effect happens because of the influence of other planets on a particular planet's orbit.
D)Orbits must be elliptical in shape.

Question 79

How does a rocket launch upwards? Choose the statement that best describes why a rocket goes up.

A)By expelling gas, the rocket loses mass; because it is lighter, it rises up.
B)By expelling gas downwards, the rocket is propelled upwards.
C)By expelling gas downwards, which pushes against the ground, the rocket is propelled upwards.

Question 80

The energy attributed to an object by virtue of its motion is known as .

A)radiative energy
B)kinetic energy
C)potential energy
D)mass- energy