Question 1

A 1000-kg truck moving at 10 m/s that brakes to a stop in 5 s has an average braking force of

Accepted Answer

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

Question 2

Two billiard balls having the same mass roll toward each other at the same speed.What is the net momentum of the two-ball system?

Accepted Answer

A)  0 kg∙m/s
B)  10 kg∙m/s
C)  not enough information

Question 3

A machine puts out 100 W of power for every 1000 W put into it.The efficiency of the machine is

Accepted Answer

A)  10%.
B)  50%.
C)  90%.
D)  110%.
E)  none of the above

Question 4

If you exert 6 N across a distance of 2 m in 3 s you'll deliver a power of

Accepted Answer

A)  1 W.
B)  3 W.
C)  4 W.
D)  6 W.
E)  more than 6 W

Question 5

The unit kilowatt-hour is a unit of

Accepted Answer

A)  energy.
B)  momentum.
C)  power.
D)  time.

Question 6

Jogging Jake runs along the top of a moving flatcar in the direction of motion of the flatcar.If he runs in the opposite direction,the combined momentum of Jake and the flatcar relative to an observer at rest will be

Accepted Answer

A)  more.
B)  the same.
C)  less.

Question 7

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

Accepted Answer

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

Question 8

When a cannon fires a cannonball at a given speed,the smaller recoil speed of the cannon is due to differences in

Accepted Answer

A)  forces.
B)  times.
C)  masses.
D)  momenta.

Question 9

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

Question 10

A melon is projected into the air with 100 J of kinetic energy in the presence of air resistance.When it returns to its initial level its kinetic energy is

Accepted Answer

A)  less than 100 J.
B)  more than 100 J.
C)  100 J.
D)  need more information

Question 11

What is the speed of a 4-kg ball with a momentum of 12 kg∙m/s?

Accepted Answer

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

Question 12

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

Accepted Answer

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

Question 13

A heavy truck and a small car roll down a hill at the same speed and need to stop in the same amount of time.Compared with the force to stop the car,the force needed to stop the truck is

Accepted Answer

A)  greater.
B)  smaller.
C)  the same.

Question 14

Which of these forms of energy is not renewable?

Accepted Answer

A)  wind power
B)  solar power
C)  fossil fuel power
D)  photovoltaic power

Question 15

The total momentum of a flock of identical birds could be zero only if the birds are

Accepted Answer

A)  taking off from the ground.
B)  flying in the same direction.
C)  flying in different directions.
D)  very tired and coming down to rest.

Question 16

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

Accepted Answer

A)  lifting the 50-kg sack
B)  lifting the 25-kg sack
C)  both require the same amount of work

Question 17

A 2-kg mass weighs 20 N and is held 4 m above the ground.Its potential energy relative to the ground is

Accepted Answer

A)  8 J.
B)  20 J.
C)  60 J.
D)  80 J.
E)  none of the above

Question 18

The order in which solar energy is converted to the kinetic energy of an automobile is

Accepted Answer

A)  photocells,electrolysis,motor,fuel cells,kinetic energy.
B)  photocells,electrolysis,fuels cells,motor,kinetic energy.
C)  electrolysis,fuel cells,photocells,motor,kinetic energy.

Question 19

A clerk can lift containers a vertical distance of 1 m,or roll them up a 2-m-long ramp to the same elevation.With the ramp,the applied force needed is

Accepted Answer

A)  half as much.
B)  twice as much.
C)  the same.

Question 20

While driving down the highway a lovebug spatters onto your windshield.Which undergoes the greater change in momentum during the time of contact?

Accepted Answer

A)  the lovebug
B)  your car
C)  both the same

Exam 3: Momentum and Energy

Which of these forms of energy is not renewable?

Correct AnswerverifiedShow Answer

The order in which solar energy is converted to the kinetic energy of an automobile is

Correct AnswerverifiedShow Answer

The unit kilowatt-hour is a unit of

Correct AnswerverifiedShow Answer

Jogging Jake runs along the top of a moving flatcar in the direction of motion of the flatcar.If he runs in the opposite direction,the combined momentum of Jake and the flatcar relative to an observer at rest will be

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A machine puts out 100 W of power for every 1000 W put into it.The efficiency of the machine is

Correct AnswerverifiedShow Answer

A melon is projected into the air with 100 J of kinetic energy in the presence of air resistance.When it returns to its initial level its kinetic energy is

Correct AnswerverifiedShow Answer

What is the speed of a 4-kg ball with a momentum of 12 kg∙m/s?

Correct AnswerverifiedShow Answer

Two billiard balls having the same mass roll toward each other at the same speed.What is the net momentum of the two-ball system?

Correct AnswerverifiedShow Answer

The total momentum of a flock of identical birds could be zero only if the birds are

Correct AnswerverifiedShow Answer

While driving down the highway a lovebug spatters onto your windshield.Which undergoes the greater change in momentum during the time of contact?

Correct AnswerverifiedShow Answer

When a cannon fires a cannonball at a given speed,the smaller recoil speed of the cannon is due to differences in

Correct AnswerverifiedShow Answer

A 1000-kg truck moving at 10 m/s that brakes to a stop in 5 s has an average braking force of

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A heavy truck and a small car roll down a hill at the same speed and need to stop in the same amount of time.Compared with the force to stop the car,the force needed to stop the truck is

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

Correct AnswerverifiedShow Answer

A 2-kg mass weighs 20 N and is held 4 m above the ground.Its potential energy relative to the ground is

Correct AnswerverifiedShow Answer

A clerk can lift containers a vertical distance of 1 m,or roll them up a 2-m-long ramp to the same elevation.With the ramp,the applied force needed is

Correct AnswerverifiedShow Answer

If you exert 6 N across a distance of 2 m in 3 s you'll deliver a power of

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified