Question 1

A firecracker bursts while freely falling. The combined momentum of its fragments

Accepted Answer

A) equals the momentum of the firecracker at the time of burst 
B) cancels to the firecracker's momentum at the time of bursting. 
C) cancels to zero. 
D) none of the above 
A) equals the momentum of the firecracker at the time of burst 
B) cancels to the firecracker's momentum at the time of bursting. 
C) cancels to zero. 
D) none of the above

Question 2

Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The magnitude of momentum for the combined wreck is

Accepted Answer

A) the same as the magnitude of momentum of either car before collision. 
B) less than the magnitude of momentum of either car before collision. 
C) greater than the magnitude of momentum of either car before collision. 
D) none of the above 
A) the same as the magnitude of momentum of either car before collision. 
B) less than the magnitude of momentum of either car before collision. 
C) greater than the magnitude of momentum of either car before collision. 
D) none of the above

Question 3

Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

Accepted Answer

A) carpeted floor provides a smaller impulse. 
B) stopping time is shorter on the carpet. 
C) stopping time is longer on the carpet. 
D) carpet provides a smaller impulse and a longer time. 
A) carpeted floor provides a smaller impulse. 
B) stopping time is shorter on the carpet. 
C) stopping time is longer on the carpet. 
D) carpet provides a smaller impulse and a longer time.

Question 4

To catch a fast-moving ball, you extend your hand forward before contact with the ball and let it ride backward in the direction of the ball's motion. Doing this reduces the force of contact on your hand principally because the

Accepted Answer

A) force of contact is reduced. 
B) relative velocity is less. 
C) time of contact is increased. 
D) time of contact is decreased. 
E) none of the above 
A) force of contact is reduced. 
B) relative velocity is less. 
C) time of contact is increased. 
D) time of contact is decreased. 
E) none of the above

Question 5

If all people, animals, trains and trucks all over the world began to walk or run towards the east (opposite the direction of Earth's spin), then

Accepted Answer

A) Earth would spin a bit faster. 
B) Earth would spin a bit slower. 
C) Earth's spin would not be affected at all. 
A) Earth would spin a bit faster. 
B) Earth would spin a bit slower. 
C) Earth's spin would not be affected at all.

Question 6

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

Accepted Answer

A) zero. 
B) twice. 
C) four times as much. 
D) unchanged. 
A) zero. 
B) twice. 
C) four times as much. 
D) unchanged.

Question 7

If you can't avoid being hit by a fast-moving object, you'll suffer a smaller contact force if you can extend that force over a

Accepted Answer

A) longer time. 
B) shorter time. 
C) both the same 
A) longer time. 
B) shorter time. 
C) both the same

Question 8

When Peter tosses an egg against a sagging sheet, the egg doesn't break due to

Accepted Answer

A) reduced impulse. 
B) reduced momentum. 
C) both of these 
D) neither of these 
A) reduced impulse. 
B) reduced momentum. 
C) both of these 
D) neither of these

Question 9

A 5000-kg freight car collides with a 10,000-kg freight car at rest. They couple upon collision and move at 2 m/s. What was the initial speed of the 5000-kg car?

Accepted Answer

A) 4 m/s 
B) 5 m/s 
C) 6 m/s 
D) 8 m/s 
E) none of the above 
A) 4 m/s 
B) 5 m/s 
C) 6 m/s 
D) 8 m/s 
E) none of the above

Question 10

It is correct to say that impulse is equal to

Accepted Answer

A) momentum. 
B) a corresponding change in momentum. 
C) force multiplied by the distance it acts. 
D) velocity multiplied by time. 
A) momentum. 
B) a corresponding change in momentum. 
C) force multiplied by the distance it acts. 
D) velocity multiplied by time.

Question 11

Two 5000-kg rail cars roll without friction (one at 1 m/s, the other at 2 m/s)toward each other on a level track. They collide, couple, and roll together with a combined momentum of

Accepted Answer

A) zero. 
B) 5000 kg m/s. 
C) 10,000 kg m/s. 
D) 15,000 kg m/s. 
A) zero. 
B) 5000 kg m/s. 
C) 10,000 kg m/s. 
D) 15,000 kg m/s.

Question 12

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

Accepted Answer

A) zero 
B) half the sum of their original momentums 
C) twice the sum of their original momentums 
D) need more information 
A) zero 
B) half the sum of their original momentums 
C) twice the sum of their original momentums 
D) need more information

Question 13

When a boxer moves into an oncoming punch, the force experienced is

Accepted Answer

A) decreased. 
B) increased. 
C) no different, but the timing is different. 
D) all of the above 
A) decreased. 
B) increased. 
C) no different, but the timing is different. 
D) all of the above

Question 14

Two identical objects in outer space, one moving at 2 m/s, the other at 1 m/s, have a head-on collision and stick together. Their combined speed after the collision is

Accepted Answer

A) 0.5 m/s. 
B) 0.33 m/s. 
C) 0.67 m/s. 
D) 1.0 m/s. 
E) none of the above 
A) 0.5 m/s. 
B) 0.33 m/s. 
C) 0.67 m/s. 
D) 1.0 m/s. 
E) none of the above

Question 15

The force that accelerates a rocket in outer space is exerted on the rocket by the

Accepted Answer

A) rocket's nose cone. 
B) rocket's wings. 
C) atmospheric pressure. 
D) exhaust gases. 
E) none of the above 
A) rocket's nose cone. 
B) rocket's wings. 
C) atmospheric pressure. 
D) exhaust gases. 
E) none of the above

Question 16

The average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5 s is

Accepted Answer

A) 1000 N. 
B) 2000 N. 
C) 3000 N. 
D) 4000 N. 
E) 5000 N. 
A) 1000 N. 
B) 2000 N. 
C) 3000 N. 
D) 4000 N. 
E) 5000 N.

Question 17

The speed of a 4-kg ball with a momentum of 12 kg m/s is

Accepted Answer

A) 3 m/s. 
B) 4 m/s. 
C) 12 m/s. 
D) 48 m/s. 
E) none of the above 
A) 3 m/s. 
B) 4 m/s. 
C) 12 m/s. 
D) 48 m/s. 
E) none of the above

Question 18

Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard. The reason he doesn't slip off the skateboard is due to

Accepted Answer

A) inertia in motion. 
B) momentum change. 
C) friction between his feet and the board. 
A) inertia in motion. 
B) momentum change. 
C) friction between his feet and the board.

Question 19

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is

Accepted Answer

A) greater with the haystack. 
B) greater with the brick wall. 
C) both the same 
A) greater with the haystack. 
B) greater with the brick wall. 
C) both the same

Question 20

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is

Accepted Answer

A) greater with the haystack. 
B) greater with the brick wall. 
C) both the same 
A) greater with the haystack. 
B) greater with the brick wall. 
C) both the same

Exam 6: Momentum

A firecracker bursts while freely falling. The combined momentum of its fragments

Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The magnitude of momentum for the combined wreck is

Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

To catch a fast-moving ball, you extend your hand forward before contact with the ball and let it ride backward in the direction of the ball's motion. Doing this reduces the force of contact on your hand principally because the

If all people, animals, trains and trucks all over the world began to walk or run towards the east (opposite the direction of Earth's spin), then

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

If you can't avoid being hit by a fast-moving object, you'll suffer a smaller contact force if you can extend that force over a

When Peter tosses an egg against a sagging sheet, the egg doesn't break due to

A 5000-kg freight car collides with a 10,000-kg freight car at rest. They couple upon collision and move at 2 m/s. What was the initial speed of the 5000-kg car?

It is correct to say that impulse is equal to

Two 5000-kg rail cars roll without friction (one at 1 m/s, the other at 2 m/s)toward each other on a level track. They collide, couple, and roll together with a combined momentum of

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

When a boxer moves into an oncoming punch, the force experienced is

Two identical objects in outer space, one moving at 2 m/s, the other at 1 m/s, have a head-on collision and stick together. Their combined speed after the collision is

The force that accelerates a rocket in outer space is exerted on the rocket by the

The average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5 s is

The speed of a 4-kg ball with a momentum of 12 kg m/s is

Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard. The reason he doesn't slip off the skateboard is due to

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is

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