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

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.

Answer 1

of gravity.

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.

Answer 2

It would fall at the same rate a rock falls when dropped on the moon.

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

Answer 3

a car while it is moving at unchanging speed up a straight [or steady] incline

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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

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

Question 21

On the moon, an object dropped from rest falls a distance of 1 m in 1 second. How far will it have fallen during 3 seconds?

A) 12 m
B) 6 m
C) 3 m
D) 18 m
E) 9 m

Question 22

Falling objects [dropped near the earth's surface, neglecting air resistance] all fall at

A) an acceleration that is larger for more massive objects.
B) the same constant [or unchanging] acceleration.
C) the same constant (or unchanging) speed.
D) the same constant [or unchanging] velocity.
E) zero acceleration.

Question 23

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 friction.
B) the ether slows it down to a stop.
C) its natural motion is to come to rest.
D) of gravity.
E) of its inertia.

Question 24

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 and different velocities.
B) they both have the same speed and the same velocity.
C) they both have the same speed but different velocities.
D) they have different speeds, but the same velocity.
E) None of the above.

Question 25

While a rock is falling straight down it has

A) an unchanging speed and an unchanging velocity.
B) a changing speed and a changing velocity.
C) a changing speed and a constant velocity.
D) an unchanging speed and a changing velocity.

Question 26

While a rock is falling straight down it has

A) an unchanging velocity.
B) zero velocity.
C) a decreasing velocity.
D) an increasing velocity.
E) None of the above.

Question 27

According to Aristotelian physics, what outside influence acts on a stone while it falls?

A) None.
B) Fire.
C) Acceleration.
D) The Olympic gods.
E) Gravity.

Question 28

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.

Question 29

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. What was its average speed during the entire first second [i.e., from t=0 until t=1 sec]?

A) 16 m/s
B) 12 m/s
C) 4 m/s
D) 8 m/s
E) None of the above.

Question 30

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

A) of electrical attraction.
B) its natural motion is to fall.
C) of gravity.
D) of friction.
E) of its inertia.

Question 31

An object is not accelerated if

A) its speed remains unchanged while its direction of motion changes.
B) its speed changes while its direction of motion remains unchanged.
C) it is acted upon by an external influence.
D) its speed and its direction of motion are both unchanging.
E) both answers B and D are correct.

Question 32

A satellite orbits the earth at an unchanging speed of 18,000 mph. This satellite

A) is accelerated.
B) has a changing velocity.
C) Both of the above.
D) None of the above.

Question 33

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

A) A stone falling straight downward.
B) A book coming to rest as it slides along the floor.
C) Both a stone falling straight downward and a sliding book coming to rest are natural motions.
D) Neither a stone falling straight downward nor a sliding book coming to rest are natural motions.

Question 34

Most meteoroids-- rocks moving through outer space--have been moving for billions of years. What, if anything, keeps them moving and why?

A) According to Newton's law of motion, their own acceleration keeps them moving.
B) According to Newton's law of gravity, the force of gravity keeps them moving.
C) According to the law of inertia, nothing is needed to keep them moving.
D) According to current theories about the creation of the universe, the big bang keeps them moving.
E) According to Newton's law of gravity, nothing is needed to keep them moving.

Question 35

Galileo's principle of falling is limited by the condition that

A) air resistance must be negligible.
B) the two objects must have the same weight.
C) Both of the above.
D) the two objects must have the same size.
E) actually, this principle has no limitations.

Question 36

In what way did Galileo improve on the physics of Aristotle?

A) Galileo understood that no force is needed to keep an object moving in a circle at constant speed.
B) Galileo understood that "natural" (or unforced) motion occurs at constant velocity.
C) Galileo understood that a force is needed to keep an object moving at constant velocity.
D) Galileo understood that energy is always conserved in every physical process.
E) Galileo understood that the gravitational force acts between every pair of objects in the universe.

Question 37

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. What is the rock's average speed during the entire first second [from t=0 until t=1 sec]?

A) 10 m/s
B) 5 m/s
C) 6 m/s
D) 0
E) 3 m/s

Question 38

According to Newtonian physics, an object with no forces acting on it must

A) be at rest.
B) either be at rest or have constant velocity.
C) be accelerated, with an unchanging acceleration.
D) eventually come to rest.
E) fall.

Question 39

A bicyclist moves around a circular track at a constant [or unchanging] speed. The bicyclist has

A) non- zero velocity but zero acceleration.
B) zero velocity and zero acceleration (in other words, no acceleration).
C) non- zero velocity and non- zero acceleration.
D) zero velocity but non- zero acceleration.
E) the heebie- jeebies.

Question 40

Which of the following describes an object that is moving with an unchanging speed but a changing velocity?

A) A car rounding a curve at a steady 80 km/hr.
B) 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.
C) A car moving along a straight horizontal (level) line at a steady 80 km/hr.
D) A car slowing down while moving along a straight line.
E) Both answers C and D are correct.

Question 41

The acceleration due to gravity is 10 m/sec². If an object falls from rest, its instantaneous speed at the end of the fifth second is (neglecting air resistance)

A) 100 m/sec.
B) 5 m/sec.
C) 10 m/sec.
D) 50 m/sec.
E) impossible to determine from the given information.

Question 42

In the figure, the moon is moving clockwise in a circular orbit around Earth. Imagine that gravity was suddenly shut off, throughout the solar system, at the instant when the moon is in the position shown in the figure. How would the moon move, after gravity was shut off?

A) In the direction of arrow B, in a straight line.
B) In the direction of arrow C, in a straight line.
C) In the direction of arrow A, in a straight line.
D) It would continue moving in the same circular path.
E) Initially in the direction of arrow A, but then curving around toward the direction of arrow B.

Question 43

While a rock is falling straight down it has

A) a constant [or unchanging] acceleration.
B) a decreasing acceleration.
C) an increasing acceleration.
D) zero acceleration.
E) None of the above.

Question 44

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

A) A stone falling straight downward.
B) A book coming to rest as it slides along the floor.
C) Both a stone falling straight downward and a sliding book coming to rest are natural motions.
D) Neither a stone falling straight downward nor a sliding book coming to rest are natural motions.

Question 45

While a rock is falling straight down with negligible air resistance, it has

A) an increasing speed.
B) a decreasing speed.
C) an unchanging speed.
D) zero speed.
E) None of the above.

Question 46

In our study of falling objects, we noted that the total distance fallen was approximately 5 m in 1 s, 20 m in 2 s, 45 m in 3 s, and 80 m in 4 s. Which of the following best describes the pattern in this data?

A) Distance is proportional to the time.
B) Distance is inversely proportional to the square of the time.
C) Distance is proportional to the square of the time.
D) The path followed by the motion is parabolic.
E) The path followed by the motion is elliptical.

Question 47

You ride a motor scooter 8 km in 15 minutes. Your [average] speed is

A) 2 km/hr.
B) 48 km/hr.
C) 16 km/hr.
D) 4 km/hr.
E) 32 km/hr.

Question 48

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.

Question 49

The figure represents a multiple- flash photo of two balls moving to the right, and shows both balls at several numbered times. In the figure,

A) the upper ball, which has a larger speed, passes the lower ball.
B) the lower ball, which has a larger acceleration, passes the upper ball.
C) the upper ball, which has a larger acceleration, passes the lower ball.
D) the lower ball, which has a larger speed, passes the upper ball.
E) neither ball passes the other ball during their motion.

Question 50

Which of the following situations represents a car whose speed is increasing?

A) In equal times, a car covers shorter and shorter distances.
B) A car covers equal distances in equal times.
C) A car takes longer and longer times to cover equal distances.
D) A car covers equal distances in shorter and shorter times.
E) None of the above.

Question 51

Which statement is the most accurate for falling objects on Earth?

A) Heavy objects fall significantly faster than light objects.
B) Neglecting the effects of air resistance, light objects fall faster than heavy objects.
C) Neglecting the effects of air resistance, heavy objects fall faster than light objects.
D) Neglecting the effects of air resistance, all objects fall at roughly the same speed.
E) All objects fall at roughly the same speed.

Question 52

In twice the time, an object will fall

A) four times as far.
B) twice as far.
C) 12 times as far.
D) eight times as far.
E) 16 times as far.

Question 53

What keeps Earth moving?

A) Actually, it isn't moving.
B) solar energy
C) gravity
D) the energy of space
E) its inertia

Question 54

On the planet Jupiter, a dropped object picks up a speed of 20 m/sec in one second. How fast will it be going at the end of 3 seconds of fall, neglecting "air" resistance on Jupiter?

A) 20 m/sec
B) 80 m/sec
C) 40 m/sec
D) 60 m/sec
E) 180 m/sec

Question 55

Is it possible for the driver of a car to accelerate the car without pressing on the accelerator?

A) Yes, by turning the steering wheel.
B) Yes, by both of the above methods.
C) Yes, by pressing on the brake.
D) No, because the only way to speed up is to press on the accelerator.
E) No, because of the way that we define the word "acceleration" in physics.

Question 56

Edgar Jones, angry at having purchased a tasteless pizza, drops his pizza off the Brooklyn bridge. As it falls, Edgar's pizza has a constant [or unchanging] (NOTE: Neglect air resistance.)

A) velocity.
B) speed.
C) acceleration.
D) position.
E) All of the above.

Question 57

According to Aristotle, 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.

Question 58

Suppose you are on the moon and you drop a rock and a feather at the same time. You will find that

A) the rock falls faster than the feather, and both speeds are the same as they would be on Earth.
B) the two fall at the same speed, but this speed is slower than a rock would fall on Earth.
C) the two fall at the same speed, and this speed is the same as the speed of a rock falling on Earth.
D) the rock falls faster than the feather, although both of them fall slower than they would on Earth.
E) they don't fall-- they remain suspended above the surface of the moon.

Question 59

Mary passes Mike from behind while bicycling. As she passes him,

A) the two have different speeds and different velocities.
B) Mike turns into a hippopotamus.
C) the two have different speeds but the same velocities.
D) the two have the same speeds but different velocities.
E) the two have the same speeds and the same velocities.

Question 60

The figure represents a multiple- flash photo of two balls moving to the right, and shows both balls at several numbered times. In the figure,

A) neither ball is accelerated, and the upper ball is moving fastest.
B) both balls are accelerated, and the lower ball is moving fastest.
C) the lower ball is accelerated, but the upper ball is not accelerated.
D) both balls are accelerated, and the upper ball is moving fastest.
E) neither ball is accelerated, and the lower ball is moving fastest.

Question 61

Jack rides a bicycle northward at 12 mph. Jill rides southward on the same road at 12 mph. As they pass each other

A) their speeds are different but their velocities are identical.
B) their speeds are identical and their velocities are identical.
C) theoretical physics predicts, surprisingly enough, that they will turn into giant frogs.
D) their speeds are different and their velocities are different.
E) their speeds are identical but their velocities are different.

Question 62

What, if any, evidence did Galileo have for the law of inertia?

A) A smooth ball slows down when rolling uphill, and speeds up when rolling downhill, so it should maintain an unchanging speed on a level surface.
B) Noting that the length of the year does not change, he concluded that Earth must maintain an unchanging speed when moving around the sun.
C) Using a telescope, he observed meteors and comets moving at unchanging velocity through outer space.
D) All of the above.
E) He didn't have direct evidence, but proposed the law of inertia only because of the known failures of Aristotelian physics.

Question 63

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) 4.8 cm/s.
B) 6 cm/s.
C) 0.4 cm/s.
D) 1.2 cm/s.
E) 0.8 cm/s.

Question 64

Is it possible for an object to accelerate but without changing its speed?

A) Yes, for example when a car is halfway up a straight hill [a hill whose slope, or angle with the horizontal, does not change] and moving a an unchanging speed.
B) Yes, for example when a car turns a corner while maintaining an unchanging speed.
C) Both of the above.
D) No, because the word "acceleration" means "a change in speed."
E) No, because the word "acceleration" means "speeding up."

Question 65

It is 6 km to Centerville, and you bicycle there in 20 minutes. Your speed is

A) 18 km/hr.
B) 24 km/hr.
C) 2 km/hr.
D) 12 km/hr.
E) 9 km/hr.

Question 66

On Mars, the acceleration due to gravity is 8 m/s/s. If an object is dropped over the surface of Mars, how fast will it be moving at the end of 3 seconds of fall?

A) 16 m/s
B) 32 m/s
C) 8 m/s
D) 72 m/s
E) 24 m/s

Question 67

A car is rounding the top, or crest, of a hill while moving at a steady 50 km/hr. What can you say about this car's acceleration, and why?

A) The car is accelerated, because its speed is changing.
B) The car is not accelerated, because its speed is not changing.
C) The car is not accelerated, because its direction of motion is not changing.
D) The car is accelerated, because its direction of motion is changing.
E) The car is not accelerated, because neither its direction of motion nor its speed are changing.

Question 68

In the "space" [or in "outer space"] between Earth and the moon there is

A) a big cloud made of chocolate fudge.
B) air, but no force due to gravity.
C) both air and a force due to gravity.
D) no air, but there is a force due to gravity.
E) no air and no force [or pull] due to gravity.

Question 69

An auto is moving at a steady 50 mph up a long straight [constant "slope"] incline. While it is on this incline,

A) its velocity is zero but its acceleration is not zero [i.e., it does have an acceleration].
B) its velocity and acceleration are both zero.
C) neither its velocity nor its acceleration are zero.
D) its acceleration is zero but its velocity is not zero.
E) it has the heebie- jeebies.

Question 70

A ball is moving at 20 m/s. If no forces act on it, then 5 seconds later the ball's speed will be

A) zero.
B) 20 m/s.
C) more than 20 m/s, but the precise answer cannot be found without further information.
D) less than 20 m/s, but the precise answer cannot be found without further information.
E) None of the above.

Question 71

Meteors in outer space keep moving, rather than slowing down and stopping. This behavior is predicted by

A) the law of force pairs.
B) Newton's law of motion.
C) Aristotle's principle of natural motion.
D) the law of inertia.
E) Galileo's law of falling.