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Energy review
1. A student applies a 20.-newton force to move a crate at a constant
speed of 4.0 meters per second across a rough floor. How much
work is done by the student on the crate in 6.0 seconds?
A) 80. J
B) 120 J
C) 240 J
D) 480 J
2. A l5.0-kilogram mass is moving at 7.50 meters per second on a
horizontal, frictionless surface. What is the total work that must
be done on the mass to increase its speed to 11.5 meters per
second?
A) 120. J
B) 422 J
C) 570. J
D) 992 J
3. A block weighing 15 Newtons is pulled to the top of an incline
that is 0.20 meter above the ground, as shown below.
7. A force of 3 Newtons moves a 10-kilogram mass horizontally a
distance of 3 meters at constant velocity. The work done against
friction is
A) 6 J
B) 9 J
C) 3 J
D) 30 J
8. If 20. joules of work is done in 4.0 seconds, the power developed
is
B) 5.0 watts
D) 80. watts
A) 0.20 watt
C) 16 watts
9. A 60.0-kilogram runner has 1920 joules of kinetic energy. At
what speed is she running?
B) 8.00 m/s
D) 64.0 m/s
A) 5.66 m/s
C) 32.0 m/s
10. In the diagram below, 55 joules of work is needed to raise a
10.-newton weight 5.0 meters.
If 4.0 joules of work are needed to pull the block the full length of
the incline, how much work is done against friction?
A) 1.0 J
B) 0.0 J
C) 3.0 J
D) 7.0 J
4. Base your answer to the following question on the diagram below
which shows a 20-newton force pulling an object up a hill at a
constant rate of 2 meters per second.
How much work is done to overcome friction as the weight is
raised?
A) 5 J
The work done against gravity in moving the object from point A
to point B is approximately
A) 100 J
B) 200 J
C) 500 J
D) 600 J
B) 5.5 J
C) 11 J
D) 50. J
11. As shown in the diagram below, a child applies a constant
20.-newton force along the handle of a wagon which makes a
25° angle with the horizontal.
5. The diagram below shows a moving, 5.00-kilogram cart at the
foot of a hill 10.0 meters high. For the cart to reach the top of the
hill, what is the minimum kinetic energy of the cart in the position
shown? [Neglect energy loss due to friction.]
A) 4.91 J
B) 50.0 J
C) 250. J
D) 491 J
6. As a box is pushed 30. meters across a horizontal floor by a
constant horizontal force of 25 newtons, the kinetic energy of the
box increases by 300. joules. How much total internal energy is
produced during this process?
A) 150 J
B) 250 J
C) 450 J
D) 750 J
How much work does the child do in moving the wagon a
horizontal distance of 4.0 meters?
A) 5.0 J
B) 34 J
C) 73 J
D) 80. J
12. An object moving at a constant speed of 25 meters per second
possesses 450 joules of kinetic energy. What is the object’s
mass?
A) 0.72 kg B) 1.4 kg
C) 18 kg
D) 36 kg
Energy review
13. A box is pushed to the right with a varying horizontal force. The graph below represents the relationship between the
applied force and the distance the box moves.
What is the total work done in moving the box 6.0 meters?
A) 9.0 J
C) 27 J
B) 18 J
14. In the diagram below, an average force of 20. Newtons is used to
pull back the string of a bow 0.60 meter.
D) 36 J
18. As a ball falls freely (without friction) toward the ground, its
total mechanical energy
A) decreases
C) remains the same
B) increases
19. While riding a chairlift, a 55-kilogram skier is raised a vertical
distance of 370 meters. What is the total change in the skier’s
gravitational potential energy?
A) 5.4 × 101J
C) 2.0 × 104 J
B) 5.4 × 102 J
D) 2.0 × 105 J
20. What is the average power required to raise a 1.81 × 104-newton
elevator 12.0 meters in 22.5 seconds?
As the arrow, leaves the bow, its kinetic energy is
A) 3.4 J
B) 6.0 J
C) 12 J
D) 33 J
15. A child does 0.20 joule of work to compress the spring in a
pop-up toy. If the mass of the toy is 0.010 kilogram, what is the
maximum vertical height that the toy can reach after the spring
is released?
A) 20. m
C) 0.20 m
A) 8.04 × 102 W
C) 2.17 × 105 W
B) 9.65 × 103 W
D) 4.89 × 106 W
21. As a pendulum swings from position A to position B as shown in
the diagram, its total mechanical energy (neglecting friction)
B) 2.0 m
D) 0.020 m
16. Sixteen joules of work was required to lift a 2.0-kilogram object
from the floor to a table. How much potential energy was
gained by the 2.0-kilogram object?
A) 0.80 joule
C) 16 joules
B) 8.0 joules
D) 32 joules
17. A 55.0-kilogram diver falls freely from a diving platform that is
3.00 meters above the surface of the water in a pool. When she
is 1.00 meter above the water, what are her gravitational
potential energy and kinetic energy with respect to the water’s
surface?
A)
B)
C)
D)
PE = 1620 J and KE = 0 J
PE = 1080 J and KE = 540 J
PE = 810 J and KE = 810 J
PE = 540 J and KE = 1080 J
A) decreases
C) remains the same
B) increases
22. A spring with a spring constant of 4.0 newtons per meter is
compressed by a force of 1.2 newtons. What is the total elastic
potential energy stored in this compressed spring?
A) 0.18 J
B) 0.36 J
C) 0.60 J
D) 4.8 J
Energy review
23. The diagram below shows a 0.1-kilogram apple attached to a
branch of a tree 2 meters above a spring on the ground below.
28. An object weighing 15 Newtons is lifted from the ground to a
height of 0.22 meter. The increase in the object’s gravitational
potential energy is approximately
A) 310 J
B) 32 J
C) 3.3 J
D) 0.34 J
29. As a ball falls freely toward the earth, its kinetic energy
A) decreases
C) remains the same
B) increases
30. The diagram below shows a toy cart possessing 16 joules of
kinetic energy traveling on a frictionless, horizontal surface
toward a horizontal spring.
The apple falls and hits the spring, compressing it 0.1 meter
from its rest position. If all of the gravitational potential energy
of the apple on the tree is transferred to the spring when it is
compressed, what is the spring constant of this spring?
A) 10 N/m
C) 100 N/m
B) 40 N/m
D) 400 N/m
24. As a bullet shot vertically upward rises, the kinetic energy of the
bullet
A) decreases
C) remains the same
B) increases
25. The work done in accelerating an object along a frictionless
horizontal surface is equal to the change in the object’s
A) momentum
C) potential energy
B) velocity
D) kinetic energy
26. In raising an object vertically at a constant speed of 2.0 meters
per second, 10. watts of power is developed. The weight of the
object is
A) 5.0 N
B) 20. N
C) 40. N
D) 50. N
27. The diagram below which represents a swinging pendulum.
The potential energy that an ideal pendulum has at point x
equals the value of its kinetic energy at point
A) A
B) B
C) C
D) D
If the cart comes to rest after compressing the spring a distance
of 1.0 meter, what is the spring constant of the spring?
A) 32 N/m
C) 8.0 N/m
B) 16 N/m
D) 4.0 N/m
Answer Key
Energy review
1.
D
2.
C
3.
A
4.
C
5.
D
6.
C
7.
B
8.
B
9.
B
10.
A
11.
C
12.
B
13.
C
14.
C
15.
B
16.
C
17.
D
18.
C
19.
D
20.
B
21.
C
22.
A
23.
D
24.
A
25.
D
26.
A
27.
B
28.
C
29.
B
30.
A