Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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A worker pushes a wheelbarrow with a force of 40 N over a level distance of 6.0
m. If a frictional force of 24 N acts on the wheelbarrow in a direction opposite to that of the
worker, what net work is done on the wheelbarrow?
a. | 240 J | b. | 216 J | c. | 144
J | d. | 96 J | e. | 75 J |
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2.
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What is the kinetic energy of a 0.135-kg baseball thrown at 40.0 m/s (90.0
mph)?
a. | 54.0 J | b. | 87.0 J | c. | 108
J | d. | 216 J | e. | 256 J |
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3.
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What is the minimum amount of energy required for an 80-kg climber carrying a
20-kg pack to climb Mt. Everest, 8 850 m high?
a. | 8.67 MJ | b. | 4.16 MJ | c. | 2.47
MJ | d. | 1.00 MJ | e. | 0.872 MJ |
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4.
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As an object is lowered into a deep hole in the surface of the earth, which of
the following must be assumed in regard to its potential energy?
a. | increase | b. | decrease | c. | remain
constant | d. | cannot tell from the information given | e. | increases up to the maximum and then remains
constant |
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5.
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Samantha pushes a 50-N crate up a ramp 25.0 m in length and inclined at 10° with the horizontal. What potential energy change does the crate
experience?
a. | 13 J | b. | 55 J | c. | 120
J | d. | 220 J | e. | 280 J |
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6.
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An amount of work equal to 1.5 J is required to compress the spring in a
spring-gun. What is the "launch speed" of a 15-g marble?
a. | 14 m/s | b. | 15 m/s | c. | 18
m/s | d. | 21 m/s | e. | 23 m/s |
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7.
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A Hooke's law spring is mounted horizontally over a frictionless surface.
The spring is then compressed a distance d and is used to launch a mass m along the
frictionless surface. What compression of the spring would result in the mass attaining double the
speed received in the above situation?
a. | 1.41 d | b. | 1.73 d | c. | 2.00
d | d. | 4.00 d | e. | 5.35 d |
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8.
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Adisa pulls a 40-N crate up a 5.0-m long inclined plane at a constant velocity.
If the plane is inclined at an angle of 37° to the horizontal and
there is a constant force of friction of 10 N between the crate and the surface, what is the net
change in potential energy of the crate?
a. | 120 J | b. | -120
J | c. | 200 J | d. | -200
J | e. | 140 J |
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9.
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A parachutist of mass 50.0 kg jumps out of an airplane at a height of 1 000 m.
The parachute deploys, and she lands on the ground with a speed of 5.0 m/s. How much energy was lost
to air friction during this jump?
a. | 49 400 J | b. | 98 700 J | c. | 198 000
J | d. | 489 000 J | e. | 534 000 J |
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10.
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The unit of power, watt, is dimensionally the same as:
a. | joule-second. | b. | joule/second. | c. | joule-meter. | d. | joule/meter. | e. | joule-kilogram. |
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11.
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A 60-kg woman runs up a flight of stairs having a rise of 4.0 m in a time of 4.2
s. What average power did she supply?
a. | 380 W | b. | 560 W | c. | 620
W | d. | 670 W | e. | 730 W |
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12.
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Yuri, a Russian weightlifter, is able to lift 250 kg 2.00 m in 2.00 s. What is
his power output?
a. | 500 W | b. | 2.45 kW | c. | 4.90
kW | d. | 9.80 kW | e. | 10.0 kW |
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13.
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A speed boat requires 80 kW to move at a constant speed of 15 m/s. What is the
resistive force of the water at this speed?
a. | 2 700 N | b. | 5 300 N | c. | 6 500
N | d. | 7 700 N | e. | 8 400 N |
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14.
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A 1 000-kg sports car accelerates from zero to 25 m/s in 7.5 s. What is the
average power delivered by the automobile engine?
a. | 20.8 kW | b. | 30.3 kW | c. | 41.7
kW | d. | 52.4 kW | e. | 67.8 kW |
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15.
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A force of 5.0 N is applied to a 20-kg mass on a horizontal frictionless
surface. As the speed of the mass increases at a constant acceleration, the power delivered to it by
the force:
a. | remains the same. | b. | increases. | c. | decreases. | d. | doubles every 4.0 seconds. | e. | halves every 4.0
seconds. |
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