Question 1

A stone is lifted and released so that it falls to the ground. According to Galileo, it fell because
A) of electrical attraction.
B) of its inertia.
C) of gravity.
D) of friction.
E) its natural motion is to fall.

Accepted Answer

Galileo's studies of motion and falling objects led to the understanding that objects fall due to gravity, which is the force of attraction between the object and the Earth.

Question 2

If a helium- filled balloon is released on Earth, it rises. How would a helium- filled balloon move if it were released a few feet above the surface of the moon?
A) It would fall, but much more slowly than a rock dropped on the moon.
B) It would rise.
C) It would fall at the same rate a rock falls when dropped on the moon.
D) It would remain suspended at the point of release.
E) It would turn into a giant pumpkin.

Accepted Answer

The moon has no atmosphere, so there is no buoyant force to make the balloon rise. It would fall due to gravity, similar to a rock.

Question 3

Which of these is not accelerating?
A) a car while it is rounding a corner at constant [or steady] speed
B) a car while it is moving at unchanging speed up a straight [or steady] incline
C) a car going over the crest of a rounded hill at a constant speed
D) a car starting up from rest
E) actually all of these cars are accelerating

Accepted Answer

A car moving at an unchanging speed up a straight incline is not accelerating because its velocity is constant and there is no change in direction.

Question 4

In twice the time, an object will attain a speed that is
A) four times as fast.
B) 12 times as fast.
C) eight times as fast.
D) 16 times as fast.
E) twice as fast.

Accepted Answer

If an object is moving with constant acceleration, its speed is directly proportional to time. Therefore, in twice the time, the speed will be twice as fast.

Question 5

In what kind of path would the planets move if no force acted on them? A) Larger elliptical orbits. B) Parabolas, like a thrown rock. C) Straight line with an acceleration of 10 m/sec². D) Straight line with no acceleration. E) They would continue in their present orbits, since they already have no force on them.

Accepted Answer

If no force acted on the planets, they would move in a straight line with no acceleration, according to Newton's first law of motion, which states that an object in motion will remain in motion in a straight line unless acted upon by an external force.

Question 6

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

Accepted Answer

The answer of You ride a motor scooter 8 km...

Question 7

A simple "do it yourself" experiment, performed in class, showing that objects accelerate as they fall is
A) using a flash camera to photograph the position of a ball at several equally- spaced times as the ball falls.
B) throwing an object horizontally from some distance above the ground, and measuring the time for it to hit the ground as compared with an object that is simply dropped from the same distance above the ground.
C) dropping an object to the floor from various heights, and measuring the time of fall.
D) dropping an object from several meters high, and measuring its position at the end of each second.
E) dropping an object to the floor from various heights, and observing the sound of the object hitting the floor.

Accepted Answer

The answer of A simple "do it yourself" experiment, performed...

Question 8

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

Accepted Answer

Aristotle believed that the natural state of objects is to be at rest, and they require a force to keep moving. Hence, he would say the book stops because its natural motion is to come to rest.

Question 9

In which of the following cases does the automobile have an acceleration?
A) An auto moving along a straight (or steady) upward incline at constant speed.
B) An auto rounding a curve at constant speed.
C) Both of the above.
D) None of the above.

Accepted Answer

An automobile rounding a curve at constant speed is accelerating because its direction is changing, which means there is a change in velocity, and acceleration is the rate of change of velocity.

Question 10

You give your physics book a quick push so that it slides along a table top. It soon slides to a stop. How would Aristotle and Galileo interpret this?
A) Both of them say the force of friction slows it to a stop.
B) Both of them say that this is just the natural motion of the book.
C) Aristotle says the force of friction slows it to a stop, but Galileo says this is just the natural motion of the book.
D) They agree that physics books can make you crazy and it's best not to think about them.
E) Aristotle says this is just the natural motion of the book, but Galileo says the force of friction slows it to a stop.

Accepted Answer

Aristotle believed that objects naturally come to rest unless a force keeps them moving, while Galileo recognized that friction is the force that causes the book to stop.

Question 11

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) 9 meters.
B) 8 meters.
C) 4 meters.
D) 16 meters.
E) 12 meters.

Accepted Answer

The answer of An astronaut drops a rock on the...

Question 12

An object is dropped from rest on the planet Jupiter. At the end of 1 second, it has fallen 8 m and is moving at 16 m/s. The total distance fallen after [i.e., at the end of] two seconds will be
A) 32 m.
B) 64 m.
C) 16 m.
D) 24 m.
E) None of the above.

Accepted Answer

The object falls 8 m in the first second and accelerates uniformly. In the second second, it falls an additional 24 m (16 m/s * 1 s + 0.5 * 8 m/s² * 1 s²), totaling 32 m after two seconds.

Question 13

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 "slope" is unchanging] at a steady 80 km/hr, when the car is midway up the hill
E) All of the above.

Accepted Answer

Acceleration occurs when there is a change in velocity, which includes changes in speed or direction. Both a car rounding a curve (change in direction) and a car slowing down (change in speed) are examples of acceleration.

Question 14

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

Accepted Answer

The answer of According to Galileo, which of these is...

Question 15

While a stone is falling [neglecting air resistance],
A) it is accelerated.
B) its speed is changing.
C) the direction of its velocity is downward.
D) All of the above.
E) None of the above.

Accepted Answer

A falling stone is accelerated due to gravity, its speed changes as it falls, and the direction of its velocity is downward.

Question 16

On Mars, an object dropped from rest falls a distance of 4 m in 1 second. How far will it fall in 2 second, neglecting "air" resistance on Mars?
A) 8 m
B) 12 m
C) 16 m
D) 32 m
E) 24 m

Accepted Answer

The distance an object falls is proportional to the square of the time it has been falling. If it falls 4 m in 1 second, it will fall 4 times that distance in 2 seconds (since 2^2 = 4), so it will fall 16 m in 2 seconds.

Question 17

An object is dropped from rest on the planet Jupiter. At the end of 1 second, it has fallen 8 m and is moving at 16 m/s. At the end of two seconds the object's speed will be
A) 64 m/s.
B) 16 m/s.
C) 48 m/s.
D) 32 m/s.
E) None of the above.

Accepted Answer

The acceleration due to gravity on Jupiter can be calculated from the given data: 16 m/s in 1 second, which is 16 m/s². After 2 seconds, the speed will be 2 * 16 m/s² = 32 m/s.

Question 18

What keeps the moon moving, i.e., why doesn't the moon slow down and stop?
A) Nuclear processes operating in the central core of the moon.
B) It is the natural motion of every object to keep moving by itself.
C) Earth's gravity keeps it moving.
D) The sun's gravity keeps it moving.
E) It actually is slowing down, and will come to rest in a few thousand more years.

Accepted Answer

According to Newton's first law of motion, an object in motion will stay in motion unless acted upon by an external force. The moon continues to move due to its inertia.

Question 19

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) 15 m
B) 20 m
C) 9 m
D) 6 m
E) 12 m

Accepted Answer

On Venus, the stone falls 3 m in the first second. Assuming constant acceleration, it will fall 3 m in the first second and an additional 9 m in the second second (since the distance fallen is proportional to the square of the time), totaling 12 m in 2 seconds.

Question 20

A rock is dropped from rest off of a high cliff on another planet, planet X. There is no atmosphere, and thus no air resistance, on planet X. At the end of 1 second, the rock is moving at a speed of 6 m/s. At the end of 2 seconds, it is moving at 12 m/s. How fast will the rock be moving at 4 seconds after being dropped?
A) 36 m/s
B) 24 m/s
C) 20 m/s
D) 40 m/s
E) 18 m/s

Accepted Answer

The rock accelerates at a constant rate of 6 m/s² (since it gains 6 m/s every second). After 4 seconds, its speed will be 4 * 6 m/s = 24 m/s.

Quiz 3: How Things Move: Galileo Asks the Right Questions

A stone is lifted and released so that it falls to the ground. According to Galileo, it fell because

If a helium- filled balloon is released on Earth, it rises. How would a helium- filled balloon move if it were released a few feet above the surface of the moon?

Which of these is not accelerating?

In twice the time, an object will attain a speed that is

In what kind of path would the planets move if no force acted on them?

You ride a motor scooter 8 km in 10 minutes. Your speed is

A simple "do it yourself" experiment, performed in class, showing that objects accelerate as they fall is

A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. According to Aristotle, it stopped because

In which of the following cases does the automobile have an acceleration?

You give your physics book a quick push so that it slides along a table top. It soon slides to a stop. How would Aristotle and Galileo interpret this?

An astronaut drops a rock on the moon. It falls 1 meter in 1 second. In 4 seconds, it falls a total distance of

An object is dropped from rest on the planet Jupiter. At the end of 1 second, it has fallen 8 m and is moving at 16 m/s. The total distance fallen after [i.e., at the end of] two seconds will be

Which of the following describes an object that is accelerated?

According to Galileo, which of these is a "natural" or "unforced" motion?

While a stone is falling [neglecting air resistance],

On Mars, an object dropped from rest falls a distance of 4 m in 1 second. How far will it fall in 2 second, neglecting "air" resistance on Mars?

An object is dropped from rest on the planet Jupiter. At the end of 1 second, it has fallen 8 m and is moving at 16 m/s. At the end of two seconds the object's speed will be

What keeps the moon moving, i.e., why doesn't the moon slow down and stop?

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.