Question 1

The conservation of momentum is most closely related to

Accepted Answer

A)   Newton's 2nd law.
B)   Newton's 1st law.
C)   Newton's 4th law
D)   Newton's 3rd law.

Question 2

A car's engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of gasoline is 40 megajoules per liter, how many kilometers per liter does
The car get?

Accepted Answer

A)   12
B)   8
C)   10
D)   14
E)   none of these

Question 3

A flower pot of mass m falls from rest to the ground below, a distance h. Which statement is correct?

Accepted Answer

A)   The speed of the pot when it hits the ground depends on m.
B)   The KE of the pot when it hits the ground does not depend on m.
C)   The KE of the pot when it hits the ground is proportional to h.
D)   The speed of the pot when it hits the ground is proportional to h.
E)   None of these are correct.

Question 4

If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficiency is

Accepted Answer

A)   60%.
B)   90%.
C)   18%.
D)   30%.
E)   none of these

Question 5

An object may have potential energy because of its

Accepted Answer

A)   momentum.
B)   location.
C)   acceleration.
D)   speed.
E)   none of these

Question 6

A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of

Accepted Answer

A)   5000 J.
B)   500 J.
C)   10 J.
D)   more than 5000 J.
E)   510 J.

Question 7

Whereas impulse involves the time that a force acts, work involves the

Accepted Answer

A)   acceleration that a force produces.
B)   time and distance that a force acts.
C)   distance that a force acts.

Question 8

If you find that twice as much work is needed to perform a task but it takes twice as much time, the amount of power required is

Accepted Answer

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

Question 9

Two identical arrows, one with twice the speed of the other, are fired into a hay bale. The faster arrow will penetrate

Accepted Answer

A)   four times as far as the slower arrow.
B)   the same distance as the slower arrow.
C)   twice as far as the slower arrow.
D)   more than four times as far as the slower arrow.
E)   none of these

Question 10

Which requires the most amount of work by the brakes of a car?

Accepted Answer

A)   slowing down from 100 km/h to 70 km/h
B)   slowing down from 70 km/h to a stop
C)   equal amounts for either

Question 11

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

Accepted Answer

A)   12 kg
B)   4 kg
C)   16 kg
D)   144 kg
E)   none of these

Question 12

A hydraulic press, like an inclined plane, is capable of increasing energy.

Accepted Answer

A)   always false
B)   sometimes false
C)   sometimes true
D)   always true

Question 13

Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick
Upon collision, their speed after collision will be

Accepted Answer

A)   1 m/s.
B)   1/4 m/s.
C)   1/5 m/s.
D)   1/6 m/s.
E)   none of these.

Question 14

A ball rolling down an incline has its maximum kinetic energy at

Accepted Answer

A)   the top.
B)   three-quarters of the way down.
C)   halfway down.
D)   the bottom.

Question 15

A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is

Accepted Answer

A)   more than 100 J.
B)   100 J.
C)   less than 100 J.
D)   not enough information given

Question 16

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

Accepted Answer

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

Question 17

A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will have a greater

Accepted Answer

A)   momentum.
B)   acceleration.
C)   speed.
D)   all of these
E)   none of these

Question 18

A golf ball is thrown at and bounces backward from a massive bowling ball that is initially at rest. After the collision, compared to the golf ball, the bowling ball has

Accepted Answer

A)   more momentum, but less kinetic energy.
B)   less momentum and less kinetic energy.
C)   more kinetic energy, but less momentum.
D)   more momentum and more kinetic energy.
E)   Not enough information is given to say.

Question 19

Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate

Accepted Answer

A)   twice as far as the slower arrow.
B)   four times as far as the slower arrow.
C)   the same distance as the slower arrow.
D)   more than four times as far as the slower arrow.
E)   none of these

Question 20

A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after this lunch is

Accepted Answer

A)   1/2 m/s.
B)   1 m/s.
C)   2/5 m/s.
D)   5/6 m/s.
E)   6/5 m/s.

Exam 5: Momentum and Energy

Which requires the most amount of work by the brakes of a car?

Correct AnswerverifiedShow Answer

A ball rolling down an incline has its maximum kinetic energy at

Correct AnswerverifiedShow Answer

A hydraulic press, like an inclined plane, is capable of increasing energy.

Correct AnswerverifiedShow Answer

Two identical arrows, one with twice the speed of the other, are fired into a hay bale. The faster arrow will penetrate

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is

Correct AnswerverifiedShow Answer

A golf ball is thrown at and bounces backward from a massive bowling ball that is initially at rest. After the collision, compared to the golf ball, the bowling ball has

Correct AnswerverifiedShow Answer

Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick Upon collision, their speed after collision will be

Correct AnswerverifiedShow Answer

A flower pot of mass m falls from rest to the ground below, a distance h. Which statement is correct?

Correct AnswerverifiedShow Answer

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

Correct AnswerverifiedShow Answer

An object may have potential energy because of its

Correct AnswerverifiedShow Answer

Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate

Correct AnswerverifiedShow Answer

A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will have a greater

Correct AnswerverifiedShow Answer

A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of

Correct AnswerverifiedShow Answer

A car's engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of gasoline is 40 megajoules per liter, how many kilometers per liter does The car get?

Correct AnswerverifiedShow Answer

If you find that twice as much work is needed to perform a task but it takes twice as much time, the amount of power required is

Correct AnswerverifiedShow Answer

A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after this lunch is

Correct AnswerverifiedShow Answer

Whereas impulse involves the time that a force acts, work involves the

Correct AnswerverifiedShow Answer

If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficiency is

Correct AnswerverifiedShow Answer

The conservation of momentum is most closely related to

Correct AnswerverifiedShow Answer

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