Question 1

Using 1000 J of work,a toy elevator is raised from the ground floor to the second floor in 20 s.How much power does the elevator use?

Accepted Answer

A)  20 W
B)  50 W
C)  100 W
D)  1000 W
E)  20,000 W

Question 2

A melon is tossed straight upward with 100 J of kinetic energy.If air resistance is negligible the melon will return to its initial level with a kinetic energy of

Accepted Answer

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

Question 3

A shopping cart moves with a kinetic energy of 40 J.If it moves at twice the speed,its kinetic energy is

Accepted Answer

A)  40 J.
B)  80 J.
C)  160 J.
D)  not enough information

Question 4

A hydraulic jack is used to lift an automobile.If the input force is 200 N over a distance of 1 meter,the output force over a distance of 0.1 meter is ideally

Accepted Answer

A)  200 N.
B)  500 N.
C)  1000 N.
D)  2000 N.
E)  none of the above

Question 5

Give two explanations of why a cannonball fired from a long-barrel cannon will have a greater velocity than from a shorter cannon.

Accepted Answer

In terms of impulse-momentum,the longer ...

Question 6

After rolling half-way down an incline,a marble's kinetic energy is

Accepted Answer

A)  less than its potential energy.
B)  greater than its potential energy.
C)  the same as its potential energy.

Question 7

The source of Earth's internal energy involves

Accepted Answer

A)  kinetic energy.
B)  potential energy.
C)  radioactivity.
D)  the Sun. C

Question 8

When a hydraulic press is properly used it is capable of multiplying force input.

Accepted Answer

A)  true
B)  false
C)  true only in special cases,energy as well

Question 9

While driving down the highway a lovebug spatters onto your windshield.Which undergoes the greater impulse?

Accepted Answer

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

Question 10

When you ride your scooter you have momentum.When you ride twice as fast you have

Accepted Answer

A)  almost twice the momentum.
B)  twice the momentum.
C)  four times the momentum.
D)  none of the above

Question 11

A straw is used for a pea shooter.When you blow through the straw the speed of the emerging pea will be greater if the straw is

Accepted Answer

A)  cut in half.
B)  full length.
C)  either cut in half or full length.

Question 12

A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact.The boat

Accepted Answer

A)  moves in the direction of the wind impact force.
B)  does not move by this wind impact.
C)  moves,but in the opposite direction of the wind impact force. A

Question 13

The change in momentum of an object is equal to the

Accepted Answer

A)  force acting on it.
B)  change in its velocity.
C)  object's mass times the force acting on it.
D)  impulse that acts on it.
E)  all of the above

Question 14

A pulley system can

Accepted Answer

A)  change the direction of a force.
B)  multiply a force.
C)  both of these
D)  none of the above

Question 15

To catch a fast-moving softball with your bare hand,you extend your hand forward just before the catch and then let the ball ride backward with your hand.Doing this reduces the catching force because the

Accepted Answer

A)  relative velocity is less.
B)  relative velocity is more.
C)  time of catch is increased.
D)  time of the catch is decreased.
E)  none of the above

Question 16

No work is done by gravity on a bowling ball that rolls along a bowling alley because

Accepted Answer

A)  no force acts on the ball.
B)  no distance is covered by the ball.
C)  the force on the ball is at right angles to its motion.
D)  no potential energy converts to kinetic energy.
E)  its kinetic energy may vary.

Question 17

A cannonball fired from a long-barrel cannon will have a greater muzzle velocity because the cannonball receives a greater

Accepted Answer

A)  force.
B)  impulse.
C)  both of these
D)  none of the above

Question 18

A 5-kg fish swimming at 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s.The speed of the larger fish after lunch is

Accepted Answer

A)  1/2 m/s.
B)  1/5 m/s.
C)  1/6 m/s.
D)  2/3 m/s.
E)  3/2 m/s.

Question 19

A 2500-N pile driver ram falls 10 m and drives a post 0.1 m into the ground.The average force on the post is

Accepted Answer

A)  2500 N.
B)  25,000 N.
C)  250,000 N.
D)  2,500,000 N.

Question 20

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)  90%.
B)  60%.
C)  30%.
D)  18%.
E)  none of the above

Exam 3: Momentum and Energy

Using 1000 J of work,a toy elevator is raised from the ground floor to the second floor in 20 s.How much power does the elevator use?

Correct AnswerverifiedShow Answer

A melon is tossed straight upward with 100 J of kinetic energy.If air resistance is negligible the melon will return to its initial level with a kinetic energy of

Correct AnswerverifiedShow Answer

A shopping cart moves with a kinetic energy of 40 J.If it moves at twice the speed,its kinetic energy is

Correct AnswerverifiedShow Answer

A hydraulic jack is used to lift an automobile.If the input force is 200 N over a distance of 1 meter,the output force over a distance of 0.1 meter is ideally

Correct AnswerverifiedShow Answer

Give two explanations of why a cannonball fired from a long-barrel cannon will have a greater velocity than from a shorter cannon.

Correct AnswerverifiedIn terms of impulse-momentum,the longer ...View AnswerShow Answer

After rolling half-way down an incline,a marble's kinetic energy is

Correct AnswerverifiedShow Answer

The source of Earth's internal energy involves

Correct AnswerverifiedC

When a hydraulic press is properly used it is capable of multiplying force input.

Correct AnswerverifiedShow Answer

While driving down the highway a lovebug spatters onto your windshield.Which undergoes the greater impulse?

Correct AnswerverifiedC

When you ride your scooter you have momentum.When you ride twice as fast you have

Correct AnswerverifiedShow Answer

A straw is used for a pea shooter.When you blow through the straw the speed of the emerging pea will be greater if the straw is

Correct AnswerverifiedShow Answer

A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact.The boat

Correct AnswerverifiedA

The change in momentum of an object is equal to the

Correct AnswerverifiedShow Answer

A pulley system can

Correct AnswerverifiedShow Answer

To catch a fast-moving softball with your bare hand,you extend your hand forward just before the catch and then let the ball ride backward with your hand.Doing this reduces the catching force because the

Correct AnswerverifiedShow Answer

No work is done by gravity on a bowling ball that rolls along a bowling alley because

Correct AnswerverifiedShow Answer

A cannonball fired from a long-barrel cannon will have a greater muzzle velocity because the cannonball receives a greater

Correct AnswerverifiedShow Answer

A 5-kg fish swimming at 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s.The speed of the larger fish after lunch is

Correct AnswerverifiedShow Answer

A 2500-N pile driver ram falls 10 m and drives a post 0.1 m into the ground.The average force on the post is

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

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In terms of impulse-momentum,the longer ...
View Answer

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C

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C

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A

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