Question 1

An object is acted upon by a force that represented by the force vs.position graph in the figure.What is the work done as the object moves
(a) from 4 m to 6 m?
(b) from 6 m to 12 m?

Accepted Answer

(a)20 J
(b)30 J

Question 2

You slam on the brakes of your car in a panic,and skid a certain distance on a straight,level road. If you had been traveling twice as fast,what distance would the car have skidded,under identical conditions?

Accepted Answer

A)  It would have skidded 4 times farther. 
B)  It would have skidded 2 times farther. 
C)  It would have skidded   times farther. 
D)  It would have skidded 1/   times farther. 
E)  It would have skidded 1/2 as far. 
A)  It would have skidded 4 times farther. 
B)  It would have skidded 2 times farther. 
C)  It would have skidded   times farther. 
D)  It would have skidded 1/   times farther. 
E)  It would have skidded 1/2 as far. A

Question 3

A box of mass m is pressed against (but is not attached to)an ideal spring of force constant k and negligible mass,compressing the spring a distance x.After it is released,the box slides up a frictionless incline as shown in the figure and eventually stops.If we repeat this experiment but instead use a spring having force constant 2k

Accepted Answer

A)  the box will go up the incline twice as high as before. 
B)  just as it moves free of the spring, the kinetic energy of the box will be twice as great as before. 
C)  just as it moves free of the spring, the speed of the box will be   times as great as before. 
D)  All of the above choices are correct. 
E)  None of the above choices is correct. 
A)  the box will go up the incline twice as high as before. 
B)  just as it moves free of the spring, the kinetic energy of the box will be twice as great as before. 
C)  just as it moves free of the spring, the speed of the box will be   times as great as before. 
D)  All of the above choices are correct. 
E)  None of the above choices is correct. D

Question 4

A constant horizontal pull acts on a sled on a horizontal frictionless ice pond.The sled starts from rest.When the pull acts over a distance x,the sled acquires a speed v and a kinetic energy K.If the same pull instead acts over twice this distance:

Accepted Answer

A)  The sled's speed will be 2v and its kinetic energy will be 2K. 
B)  The sled's speed will be 2v and its kinetic energy will be K   
C)  The sled's speed will be v   and its kinetic energy will be 2K. 
D)  The sled's speed will be v   and its kinetic energy will be K
  
E)  The sled's speed will be 4v and its kinetic energy will be 2K. 
A)  The sled's speed will be 2v and its kinetic energy will be 2K. 
B)  The sled's speed will be 2v and its kinetic energy will be K   
C)  The sled's speed will be v   and its kinetic energy will be 2K. 
D)  The sled's speed will be v   and its kinetic energy will be K
  
E)  The sled's speed will be 4v and its kinetic energy will be 2K.

Question 5

A tennis ball bounces on the floor three times.If each time it loses 22.0% of its energy due to heating,how high does it rise after the third bounce,provided we released it 2.3 m from the floor?

Accepted Answer

A)  110 cm 
B)  11 cm 
C)  110 mm 
D)  140 cm 
A)  110 cm 
B)  11 cm 
C)  110 mm 
D)  140 cm

Question 6

A force F = bx3 acts in the x direction,where the value of b is 3.7 N/m3. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

Accepted Answer

A)  42 J 
B)  13 J 
C)  50 J 
D)  57 J 
A)  42 J 
B)  13 J 
C)  50 J 
D)  57 J

Question 7

A crane lifts a 425 kg steel beam vertically a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces.

Accepted Answer

A)  5.8 × 105 J 
B)  3.4 × 105 J 
C)  4.0 × 105 J 
D)  4.9 × 105 J 
A)  5.8 × 105 J 
B)  3.4 × 105 J 
C)  4.0 × 105 J 
D)  4.9 × 105 J

Question 8

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m. (Assume an accuracy of 2 significant figures for the numbers on the graph.)

Accepted Answer

A)  26 J 
B)  29 J 
C)  22 J 
D)  35 J 
E)  27 J 
A)  26 J 
B)  29 J 
C)  22 J 
D)  35 J 
E)  27 J

Question 9

A spring-loaded dart gun is used to shoot a dart straight up into the air,and the dart reaches a maximum height of 24 meters above its point of release.The same dart is shot up a second time from the same gun,but this time the spring is compressed only half as far (compared to the first shot).How far up does the dart go this time? (Neglect friction and assume the spring is ideal and massless.)

Accepted Answer

A)  6.0 m 
B)  12 m 
C)  3.0 m 
D)  48 m 
A)  6.0 m 
B)  12 m 
C)  3.0 m 
D)  48 m

Question 10

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on the object during a displacement from x = -2.00 m to x = 2.00 m.(Assume an accuracy of 3 significant figures for the numbers on the graph.)

Accepted Answer

A)  -12.0 J 
B)  -3.00 J 
C)  -1.00 J 
D)  12.0 J 
E)  3.00 J 
A)  -12.0 J 
B)  -3.00 J 
C)  -1.00 J 
D)  12.0 J 
E)  3.00 J

Question 11

Two identical balls are thrown directly upward,ball A at speed v and ball B at speed 2v,and they feel no air resistance.Which statement about these balls is correct?

Accepted Answer

A)  Ball B will go twice as high as ball A because it had twice the initial speed. 
B)  Ball B will go four times as high as ball A because it had four times the initial kinetic energy. 
C)  The balls will reach the same height because they have the same mass and the same acceleration. 
D)  At its highest point, ball B will have twice as much gravitational potential energy as ball A because it started out moving twice as fast. 
E)  At their highest point, the acceleration of each ball is instantaneously equal to zero because they stop for an instant. 
A)  Ball B will go twice as high as ball A because it had twice the initial speed. 
B)  Ball B will go four times as high as ball A because it had four times the initial kinetic energy. 
C)  The balls will reach the same height because they have the same mass and the same acceleration. 
D)  At its highest point, ball B will have twice as much gravitational potential energy as ball A because it started out moving twice as fast. 
E)  At their highest point, the acceleration of each ball is instantaneously equal to zero because they stop for an instant.

Question 12

A stock person at the local grocery store has a job consisting of the following five segments:
(1)picking up boxes of tomatoes from the stockroom floor
(2)accelerating to a comfortable speed
(3)carrying the boxes to the tomato display at constant speed
(4)decelerating to a stop
(5)lowering the boxes slowly to the floor.
During which of the five segments of the job does the stock person do positive work on the boxes?

Accepted Answer

A)  (1) and (5) 
B)  (1) only 
C)  (1), (2), (4), and (5) 
D)  (1) and (2) 
E)  (2) and (3) 
A)  (1) and (5) 
B)  (1) only 
C)  (1), (2), (4), and (5) 
D)  (1) and (2) 
E)  (2) and (3)

Question 13

Which,if any,of the following statements concerning the work done by a conservative force is NOT true?

Accepted Answer

A)  It can always be expressed as the difference between the initial and final values of a potential energy function. 
B)  It is independent of the path of the body and depends only on the starting and ending points. 
C)  When the starting and ending points are the same, the total work is zero. 
D)  All of the above statements are true. 
E)  None of the above statements are true. 
A)  It can always be expressed as the difference between the initial and final values of a potential energy function. 
B)  It is independent of the path of the body and depends only on the starting and ending points. 
C)  When the starting and ending points are the same, the total work is zero. 
D)  All of the above statements are true. 
E)  None of the above statements are true.

Question 14

A child pulls on a wagon with a horizontal force of 75 N. If the wagon moves horizontally a total of 42 m in 3.0 min,what is the average power generated by the child?

Accepted Answer

A)  18 W 
B)  22 W 
C)  24 W 
D)  27 W 
A)  18 W 
B)  22 W 
C)  24 W 
D)  27 W

Question 15

The work performed as a function of time for a process is given by W = at3,where a = 2.4 J/s3. What is the instantaneous power output at t = 3.7 s?

Accepted Answer

A)  99 W 
B)  69 W 
C)  139 W 
D)  208 W 
A)  99 W 
B)  69 W 
C)  139 W 
D)  208 W

Question 16

Two stones,one of mass m and the other of mass 2m,are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance.Which statement about these stones is true?

Accepted Answer

A)  The heavier stone will go twice as high as the lighter one because it initially had twice as much kinetic energy. 
B)  Both stones will reach the same height because they initially had the same amount of kinetic energy. 
C)  At their highest point, both stones will have the same gravitational potential energy because they reach the same height. 
D)  At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy. 
E)  The lighter stone will reach its maximum height sooner than the heavier one. 
A)  The heavier stone will go twice as high as the lighter one because it initially had twice as much kinetic energy. 
B)  Both stones will reach the same height because they initially had the same amount of kinetic energy. 
C)  At their highest point, both stones will have the same gravitational potential energy because they reach the same height. 
D)  At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy. 
E)  The lighter stone will reach its maximum height sooner than the heavier one.

Question 17

In the figure,a 5.00-kg block is moving at 5.00 m/s along a horizontal frictionless surface toward an ideal massless spring that is attached to a wall.After the block collides with the spring,the spring is compressed a maximum distance of 0.68 m.What is the speed of the block when it has moved so that the spring is compressed to only one-half of the maximum distance?

Accepted Answer

The answer of In the figure,a 5.00-kg block is moving...

Question 18

A 4.0-kg object is moving with speed 2.0 m/s.A 1.0-kg object is moving with speed 4.0 m/s.Both objects encounter the same constant braking force,and are brought to rest.Which object travels the greater distance before stopping?

Accepted Answer

A)  the 4.0-kg object 
B)  the 1.0-kg object 
C)  Both objects travel the same distance. 
D)  It is impossible to know without knowing how long each force acts. 
A)  the 4.0-kg object 
B)  the 1.0-kg object 
C)  Both objects travel the same distance. 
D)  It is impossible to know without knowing how long each force acts.

Question 19

A 4.00-kg mass is attached to a very light ideal spring hanging vertically and hangs at rest in the equilibrium position. The spring constant of the spring is 1.00 N/cm. The mass is pulled downward 2.00 cm and released. What is the speed of the mass when it is 1.00 cm above the point from which it was released?

Accepted Answer

A)  0.0443 m/s 
B)  0.0744 m/s 
C)  0.0201 m/s 
D)  0.0866 m/s 
E)  The mass will not reach the height specified. 
A)  0.0443 m/s 
B)  0.0744 m/s 
C)  0.0201 m/s 
D)  0.0866 m/s 
E)  The mass will not reach the height specified.

Question 20

A box of mass m is pressed against (but is not attached to)an ideal spring of force constant k and negligible mass,compressing the spring a distance x.After it is released,the box slides up a frictionless incline as shown in the figure and eventually stops.If we repeat this experiment with a box of mass 2m

Accepted Answer

A)  the lighter box will go twice as high up the incline as the heavier box. 
B)  just as it moves free of the spring, the lighter box will be moving twice as fast as the heavier box. 
C)  both boxes will have the same speed just as they move free of the spring. 
D)  both boxes will reach the same maximum height on the incline. 
E)  just as it moves free of the spring, the heavier box will have twice as much kinetic energy as the lighter box. 
A)  the lighter box will go twice as high up the incline as the heavier box. 
B)  just as it moves free of the spring, the lighter box will be moving twice as fast as the heavier box. 
C)  both boxes will have the same speed just as they move free of the spring. 
D)  both boxes will reach the same maximum height on the incline. 
E)  just as it moves free of the spring, the heavier box will have twice as much kinetic energy as the lighter box.

Exam 9: Work

An object is acted upon by a force that represented by the force vs.position graph in the figure.What is the work done as the object moves (a) from 4 m to 6 m? (b) from 6 m to 12 m?

You slam on the brakes of your car in a panic,and skid a certain distance on a straight,level road. If you had been traveling twice as fast,what distance would the car have skidded,under identical conditions?

A constant horizontal pull acts on a sled on a horizontal frictionless ice pond.The sled starts from rest.When the pull acts over a distance x,the sled acquires a speed v and a kinetic energy K.If the same pull instead acts over twice this distance:

A tennis ball bounces on the floor three times.If each time it loses 22.0% of its energy due to heating,how high does it rise after the third bounce,provided we released it 2.3 m from the floor?

A force F = bx3 acts in the x direction,where the value of b is 3.7 N/m3. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

A crane lifts a 425 kg steel beam vertically a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces.

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m. (Assume an accuracy of 2 significant figures for the numbers on the graph.)

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on the object during a displacement from x = -2.00 m to x = 2.00 m.(Assume an accuracy of 3 significant figures for the numbers on the graph.)

Two identical balls are thrown directly upward,ball A at speed v and ball B at speed 2v,and they feel no air resistance.Which statement about these balls is correct?

Which,if any,of the following statements concerning the work done by a conservative force is NOT true?

A child pulls on a wagon with a horizontal force of 75 N. If the wagon moves horizontally a total of 42 m in 3.0 min,what is the average power generated by the child?

The work performed as a function of time for a process is given by W = at3,where a = 2.4 J/s3. What is the instantaneous power output at t = 3.7 s?

Two stones,one of mass m and the other of mass 2m,are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance.Which statement about these stones is true?

A 4.0-kg object is moving with speed 2.0 m/s.A 1.0-kg object is moving with speed 4.0 m/s.Both objects encounter the same constant braking force,and are brought to rest.Which object travels the greater distance before stopping?

Foundations

A: Foundations

Motion in One Dimension

Acceleration

Momentum

Energy

Principle of Relativity

Interactions

Force

Motion in a Plane

Motion in a Circle

Torque

Gravity

Special Relativity

Periodic Motion

Waves in One Dimension

Waves in Two and Three Dimensions

Fluids

Entropy

Energy Transferred Thermally

Degradation of Energy

Electric Interactions

The Electric Field

Gausss Law

Work and Energy in Electrostatics

Charge Separation and Storage

Magnetic Interactions

Magnetic Fields of Charged Particles in Motion

Changing Magnetic Fields

Changing Electric Fields

Electric Circuits

Electronics

Ray Optics

Wave and Particle Optics

Filters

A force F = bx³ acts in the x direction,where the value of b is 3.7 N/m³. How much work is done by this force in moving an object from x = 0.00 m to x = 2.6 m?

A crane lifts a 425 kg steel beam vertically a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.

The work performed as a function of time for a process is given by W = at³,where a = 2.4 J/s³. What is the instantaneous power output at t = 3.7 s?