**Unformatted text preview: **CHAPTER 6
ENERGY
111
READINESS ASSURANCE TEST (RAT)
If you have a good handle on this chapter-if you really
6. A shiny sports car at the top of a vertical cliff has a
do-then you should be able to score 7 out of 10 on this
potential energy of 100 MJ relative to the ground
RAT. Check your answers with your teacher. If you score
less than 7, study further before moving on.
below. Unfortunately, a mishap occurs and it falls
over the edge. When it is halfway to the ground, its
Choose the best answer to the following.
kinetic energy is
100 .10 - 2 - Wo .3
(a) the same as its potential energy at that point.( (-f)
1. How much work is done on a 100-kg crate that is
(b) negligible.
hoisted 2 m in a time of 4 s?
(c) about 60 MJ.
(a) 200 J
(d) more than 60 MJ.
(b) 500 J
WzFXD =7 - WOJ
(c) 800 J
(d) 2000 J
mg
K
7. When a hybrid car brakes to a stop, much of its
1000
kinetic energy is transformed to
(a) heat.
2. How much power is required to raise a 100=kg
(b) work.
crate a vertical distance of 2 m in a time of 4 s?
(c) electric potential energy.
(a) 200 W
b
500 W
Power
Work -160-10 .2- Wod
(d) gravitational potential energy.
(c)
800 W
time
d) 2000 W
K o. In an ideal pulley system, a woman lifts a 100-N
crate by pulling a rope downward with a force of
25 N. For every 1-meter length of rope she pulls
3. Raising an auto in a service station increases its
downward, the crate rises
potential energy. Raising it twice as high increases
(a) 50 centimeters.
its potential energy by
(b) 45 centimeters.
28 x
(a) half.
double kept
(c) 25 centimeters.
(b) the same amount.
td) None of these.
tc) twice.
d) four times.
Jovwol potminl ede ty 9. When 100 J are put into a device that puts out 40 ],
the efficiency of the device is
4. A model airplane moves three times as fast as
(a) 40%.
another identical model airplane. Compared to the
(b) 50%.
kinetic energy of the slower airplane, the kinetic
(c) 60%.
energy of the faster airplane is
(d) 140%.
(a) the same for level flight.
(b) twice as much
10. A machine cannot multiply
(a) forces.
(c) four times as much.
(b) distances.
(d) more than four times as much.
Ic) energy.
5. Which of the following equations is most useful
(d) All of these.
for solving a problem that asks for the distance a
fast-moving box slides across a post office floor
and comes to a stop?
(a) F = ma
(b) Ft= Amv
(c) KE = 1/2 mv?
d) Fa= 41/2 mv?...

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- Spring '17
- Dr. S. Fazal Wahid
- Potential Energy