Question 1

Two identical freight 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 together,and roll away in the direction that

Accepted Answer

A) the slower car was initially going. 
B) the faster car was initially going. 
C) Neither of these.They stop. 
A) the slower car was initially going. 
B) the faster car was initially going. 
C) Neither of these.They stop.

Question 2

A car that travels twice as fast as another when braking to a stop will skid

Accepted Answer

A) twice as far. 
B) four times as far. 
C) depends on the mass of the cars 
A) twice as far. 
B) four times as far. 
C) depends on the mass of the cars

Question 3

A moving object has

Accepted Answer

A) speed. 
B) velocity. 
C) momentum. 
D) energy. 
E) all of these 
A) speed. 
B) velocity. 
C) momentum. 
D) energy. 
E) all of these

Question 4

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

Accepted Answer

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

Question 5

An object lifted 10 meters gains 200 J of potential energy.If the same object is lifted 20 meters,its potential energy gain is

Accepted Answer

A) half as much. 
B) the same. 
C) twice as much. 
D) four times as much. 
E) more than four times as much. 
A) half as much. 
B) the same. 
C) twice as much. 
D) four times as much. 
E) more than four times as much.

Question 6

Do 100 J of work in 50 s and your power output is

Accepted Answer

A) 1/2 W 
B) 2 W. 
C) 4 W. 
D) 50 W. 
E) 5,000 W. 
A) 1/2 W 
B) 2 W. 
C) 4 W. 
D) 50 W. 
E) 5,000 W.

Question 7

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

Question 8

A 2-kg mass is held 4 m above the ground.What is the approximate potential energy of the mass with respect to the ground?

Accepted Answer

A) 6 J 
B) 8 J 
C) 32 J 
D) 80 J 
E) none of these 
A) 6 J 
B) 8 J 
C) 32 J 
D) 80 J 
E) none of these

Question 9

A woman carries a heavy box across a room at a constant speed.How much work does she do on the box while walking?

Accepted Answer

A) none 
B) More information is needed about the weight of the box. 
C) More information is needed about the distance walked. 
D) More information is needed about the speed and the distance. 
E) More information is needed about the weight,distance,and her speed. 
A) none 
B) More information is needed about the weight of the box. 
C) More information is needed about the distance walked. 
D) More information is needed about the speed and the distance. 
E) More information is needed about the weight,distance,and her speed.

Question 10

When properly used,a hydraulic press,like a wheel and axle,is capable of multiplying force input.

Accepted Answer

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

Question 11

A bow is drawn so that it has 40 J of potential energy.When fired,the arrow will ideally have a kinetic energy that is

Accepted Answer

A) less than 40 J. 
B) more than 40 J. 
C) 40 J. 
D) impossible to predict without additional information 
A) less than 40 J. 
B) more than 40 J. 
C) 40 J. 
D) impossible to predict without additional information

Question 12

A 2 kg mass has 40 J of potential energy with respect to the ground.Approximately how high is it above the ground?

Accepted Answer

A) 1 m 
B) 2 m 
C) 3 m 
D) 4 m 
E) none of these 
A) 1 m 
B) 2 m 
C) 3 m 
D) 4 m 
E) none of these

Question 13

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 the ball's motion. 
D) no potential energy is being converted to kinetic energy. 
E) its kinetic energy remains constant. 
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 the ball's motion. 
D) no potential energy is being converted to kinetic energy. 
E) its kinetic energy remains constant.

Question 14

What task requires the most work;lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?

Accepted Answer

A) the 50-kg sack 
B) the 25-kg sack 
C) Both require the same amount of work. 
D) impossible to determine without knowing the contents of the sack 
A) the 50-kg sack 
B) the 25-kg sack 
C) Both require the same amount of work. 
D) impossible to determine without knowing the contents of the sack

Question 15

Using 1000 J of work,a toy elevator is raised from the ground floor to the second floor in 20 seconds.The power needed to do this job was

Accepted Answer

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

Question 16

If you push an object a given distance,while applying twice the force,you do

Accepted Answer

A) twice as much work. 
B) four times as much work. 
C) the same amount of work. 
D) half as much work. 
A) twice as much work. 
B) four times as much work. 
C) the same amount of work. 
D) half as much work.

Question 17

Both a 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time.The power expended in raising the 50-kg sack is

Accepted Answer

A) twice as much. 
B) half as much. 
C) the same. 
D) impossible to predict without further information 
A) twice as much. 
B) half as much. 
C) the same. 
D) impossible to predict without further information

Question 18

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

Question 19

A ball rolling down an incline has its minimum speed

Accepted Answer

A) at the end the incline. 
B) half way down the incline. 
C) near the top of the incline. 
D) impossible to predict without knowing the ball's mass 
E) impossible to predict without knowing the size of the ball 
A) at the end the incline. 
B) half way down the incline. 
C) near the top of the incline. 
D) impossible to predict without knowing the ball's mass 
E) impossible to predict without knowing the size of the ball

Question 20

A TV set is pushed a distance of 2 m with a force of 20 N.How much work is done on the set?

Accepted Answer

A) 2 J 
B) 10 J 
C) 20 J 
D) 40 J 
E) 800 J 
A) 2 J 
B) 10 J 
C) 20 J 
D) 40 J 
E) 800 J

Exam 7: Energy

Two identical freight 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 together,and roll away in the direction that

A car that travels twice as fast as another when braking to a stop will skid

A moving object has

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

An object lifted 10 meters gains 200 J of potential energy.If the same object is lifted 20 meters,its potential energy gain is

Do 100 J of work in 50 s and your power output is

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

A 2-kg mass is held 4 m above the ground.What is the approximate potential energy of the mass with respect to the ground?

A woman carries a heavy box across a room at a constant speed.How much work does she do on the box while walking?

When properly used,a hydraulic press,like a wheel and axle,is capable of multiplying force input.

A bow is drawn so that it has 40 J of potential energy.When fired,the arrow will ideally have a kinetic energy that is

A 2 kg mass has 40 J of potential energy with respect to the ground.Approximately how high is it above the ground?

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

What task requires the most work;lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?

Using 1000 J of work,a toy elevator is raised from the ground floor to the second floor in 20 seconds.The power needed to do this job was

If you push an object a given distance,while applying twice the force,you do

Both a 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time.The power expended in raising the 50-kg sack is

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

A ball rolling down an incline has its minimum speed

A TV set is pushed a distance of 2 m with a force of 20 N.How much work is done on the set?

About Science

Newtons First Law of Motion: Inertia

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