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2.11 4. A car moving at 60 km/h comes to a stop in 10 s when the
mass × velocity squared
__ driver slams on the brakes. In this situation, what does 60 km/h

centripetal force =
radius of circle represent?
_ 2 a. Average speed
mv
F =

r b. Final speed
2.12 c. Initial speed
___
one mass × another mass

gravitational force = constant × d. Constant speed

distance squared
5. A car moving at 60 km/h comes to a stop in 10 s when the driver
_ slams on the brakes. In this situation, what is the fi nal speed?
m 1 m 2

F= G 2
d a. 60 km/h
b. 0 km/h
KEY TERMS c. 0.017 km/s
d. 0.17 km/s
6. According to Galileo, an object moving without opposing
acceleration (p. 29)
friction or other opposing forces will
centrifugal force (p. 49)
a. still need a constant force to keep it moving at a constant
centripetal force (p. 48)
speed.
first law of motion (p. 41) b. need an increasing force, or it will naturally slow and then
force (p. 32) come to a complete stop.
free fall (p. 36) c. continue moving at a constant speed.
fundamental forces (p. 32) d. undergo a gradual acceleration.
g (p. 38) 7. In free fall, an object is seen to have a (an)
geosynchronous satellite (p. 52) a. constant velocity.
impulse (p. 48) b. constant acceleration.
inertia (p. 34) c. increasing acceleration.
law of conservation of momentum (p. 46) d. decreasing acceleration.
mass (p. 43) 8. A tennis ball is hit, causing it to move upward from the racket at
momentum (p. 46) some angle to the horizon before it curves back to the surface in
net force (p. 32) the path of a parabola. While it moves along this path,
a. the horizontal speed remains the same.
newton (p. 43)
b. the vertical speed remains the same.
second law of motion (p. 43)
c. both the horizontal and vertical speeds remain the same.
speed (p. 27)
d. both the horizontal and vertical speeds change.
third law of motion (p. 45) 2
9. A quantity of 5 m/s is a measure of
universal law of gravitation (p. 49)
a. metric area.
velocity (p. 29) b. acceleration.
c. speed.
d. velocity.
APPLYING THE CONCEPTS

10. An automobile has how many different devices that can cause it
to undergo acceleration?
1. A straight-line distance covered during a certain amount of time a. None
describes an object’s b. One
a. speed. c. Two
b. velocity. d. Three or more

c. acceleration.
11. Ignoring air resistance, an object falling toward the surface of
d. any of the above.
Earth has a velocity that is
2. How fast an object is moving in a particular direction is a. constant.
described by b. increasing.
a. speed. c. decreasing.
b. velocity. d. acquired instantaneously but dependent on the weight of the
c. acceleration. object.
d. none of the above.
12. Ignoring air resistance, an object falling near the surface of Earth
3. Acceleration occurs when an object undergoes has an acceleration that is
a. a speed increase. a. constant.
b. a speed decrease. b. increasing.
c. a change in the direction of travel. c. decreasing.
d. any of the above. d. dependent on the weight of the object.
56 CHAPTER 2 Motion 2-32