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PPT
Work, Potential Energy, Kinetic Energy, Power
Name
Period
Date
For each problem,
 read the question carefully, choose the best answer and,
 on multiple choice questions, mark the Scantron sheet (match the question number) or
 fill in the blank(s) or
 follow the instructions for that problem.
 Don’t forget the units in your answers! Show your work for partial credit.
W
1) P = t
t=
mv2
2) mgh = 2
v =
Simplify your answer.
3) Almost all of the energy that humans use ultimately comes from
a) oil
b) gas
c) the sun
d) plants, either living or fossilized
e) volcanoes
4) Calories are a measure of
a) force
b) energy
c) mass
d) weight
e) acceleration
5) About how many Calories per day does an average person with a moderate level of
activity require?
a) 600
b) 1,200
c) 2,500
d) 5,000
e) 10,000
6) If you lift a 20 N object 2 m straight up, how much work have you done on it?
a) 40 N
b) 0.1 J
c) 10 kg
d) 40 J
e) 10 J
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PPT
Work, Potential Energy, Kinetic Energy, Power
7) If you push on a 300 kg rock with a force of 1,000 N for 10 s, and it doesn't move, how
much work have you done on the rock?
a) 0 J
b) 10,000 J
c) 300,000 J
d) 3,000,000 J
e) not enough information
8) If you push identical boxes from the bottom of each ramp to the same height at the top,
which ramp would require you to do the most work on the box? Ignore friction.
a
b
c
d
e) all the same
9) If you drive your 1,000 kg car from sea level up to the Nu'uanu Pali lookout, which is
366 m above sea level, how much will you have increased your car's potential energy?
a) 366,000 J
b) 3,660,000 J
c) 2.73 J
d) 20.73 J
e) 0.366 J
10) What is the kinetic energy of a 4 kg rock falling through the air at 5 m/s?
a) 10 J
b) 50 J
c) 20 J
d) 200 J
e) 100 J
11) Assuming 100% efficiency, how much energy is required for a 600 N person to walk up a
3 m high flight of stairs?
a) 200 J
b) 2,000 J
c) 1,800 J
d) 18,000 J
e) it depends how fast you go up
12) How efficient are humans at converting energy into work?
a) 5-10 %
b) 10-20 %
c) 30-40 %
d) 50-60 %
e) 70-80 %
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PPT
Work, Potential Energy, Kinetic Energy, Power
13) If a rock falls from a cliff, at what point are its kinetic energy and its potential energy the
same? Ignore air resistance. Assume the potential energy is relative to the bottom of the
cliff.
a) just as it starts to fall
b) just before it hits the bottom
c) halfway down
d) never
e) not enough information
14) If a 5 kg rock falls 45 m from the top of a cliff, what is its velocity at that point? Ignore
air resistance.
a) 9.5 m/s
b) 6.7 m/s
c) 21.2 m/s
d) 225 m/s
e) 30 m/s
15) In the diagram, the ball's velocity is 6 m/s, and the height of the ramp is 1 m. What will
the ball's velocity be at the top of the ramp? Ignore friction.
a) The ball won't make it to the top of the ramp.
b) 2 m/s
c) 3 m/s
d) 4 m/s
e) 5 m/s
16) In the following setup, similar to our lab activity, find the distance D the ball will travel
horizontally before it hits the floor. h = 1 m. H = 25 m. Unlike our lab, ignore friction and
rotational kinetic energy (do not use
h
0.66).
D
=
H
D
17) All of the identical balls start at the same height. Which will have the highest velocity
when it reaches the bottom of its ramp? Ignore friction.
a
b
c
d
e) all the same
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PPT
Work, Potential Energy, Kinetic Energy, Power
18) If a Suburban and a Miata are going the same speed, but the Suburban weighs three times
as much as the Miata, how many times more kinetic energy does the Suburban have than
the Miata?
a) 1
b) 3
c) 4.5
d) 9
e) not enough information
19) Two identical (except for color) Miatas are traveling down the road. The silver one is
going three times as fast as the white one. How many times more kinetic energy does the
silver Miata have than the white one?
a) 1
b) 3
c) 4.5
d) 9
e) not enough information
20) Two identical (except for color) Dodge Neons are traveling down the road. The blue one
is going twice as fast as the green one. If their brakes generate the same amount of force,
how many times further will the blue one go than the green one before they stop?
a) 2
b) 4
c) 8
d) 16
e) not enough information
21) Where is the ball's kinetic energy the greatest?
Ignore friction.
22) How much power does it take to lift a 1,000 N load
10 m in 20 s?
a) 5 W
b) 500 W
c) 2,000 W
d) 200,000 W
e) 5,000 W
a
e) all the
same
b
c
d
23) The evil monkey is using a 1500 W motor to lift a 300 kg piano up 10 m. About how
long will it take him? Not that he would drop it on your head or anything…
a) 20 s
b) 2 s
c) 50 s
d) 45 s
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PPT
Work, Potential Energy, Kinetic Energy, Power
e) 45,000 s
24) Where do most of the Calories you consume go?
a) to fuel your brain
b) to maintain bodily functions
c) to do work on exercise activities
d) excreted as urine
e) none of the above
Extra Credit
You may have learned something in this section that isn’t on the test. Explain it. Use words,
pictures, diagrams, graphs, etc. to demonstrate your knowledge.
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Work, Potential Energy, Kinetic Energy, Power
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PPT
#
Work, Potential Energy, Kinetic Energy, Power
1.
2.
3.
4.
5.
Pts
2
2
2
2
2
W/P
√(2gh)
c
b
c
6.
7.
2
2
d
a
8.
2
e
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
b
b
c
b
c
e
d
10 m
e
b
d
b
d
b
a
b
Total
48
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Answer
Steps
7
Concept
3 variables
proportions
source of energy
Calories
energy is required for bodily
functions
work is Fd
only force in the direction of
motion counts toward work
work done on an object to raise
it is the same regardless of
path
PE = mgh
KE = mv2/2
PE = Fd
human efficiency
Total E = PE + KE
PE -> KE = mv2/2
KE -> PE
PE->KE, projectile motion
PE -> KE
KE  m
KE  v2
KE  v2
PE -> KE
P = W/t
t = W/P
most human energy goes to
normal body functions
PPT
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Work, Potential Energy, Kinetic Energy, Power
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