Chapter Assessment
Section 1 Acceleration: Mastering Concepts
54.Giveanexampleofeachofthefollowing:
a. an object that is slowing down, but has a positive acceleration
b.anobjectthatisspeedingupbuthasanegativeacceleration
c.anobjectthatismovingataconstantspeedbuthasanacceleration
SOLUTION:
a. if forward is the positive direction, a car moving backward at decreasing speed
b. in the same coordinate system, a car moving backward at increasing speed
c. a car that is moving on a circular track at a constant speed
ANSWER:
a. if forward is the positive direction, a car moving backward at decreasing speed
b. in the same coordinate system, a car moving backward at increasing speed
c. a car that is moving on a circular track at a constant speed
56.If the velocity-time graph of an object moving on a straight path is a line parallel to the horizontal axis, what can you
conclude about the object’s acceleration?
SOLUTION:
When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.
ANSWER:
When the velocity-time graph is a line parallel to the horizontal axis, the acceleration is zero.
Chapter Assessment
Section 1 Acceleration: Mastering Problems
57.Ranking Task Rank the following objects according to the magnitude of the acceleration, from least to greatest.
Specificallyindicateanyties.(Level1)
A.Afallingacornacceleratesfrom0.50m/sto10.3m/sin1.0s.
B.Acaracceleratesfrom20m/storestin1.0s.
C. Acentipedeacceleratesfrom0.40cm/sto2.0cm/sin0.50s.
D.Whilebeinghit,agolfballacceleratesfromrestto4.3m/sin0.40s.
E. Ajoggeracceleratesfrom2.0m/sto1.0m/sin8.3s.
SOLUTION:
From least to greatest magnitude of acceleration: C < E < A < D < B.
A.
B.
C.
D.
E.
ANSWER:
From least to greatest magnitude of acceleration: C < E < A < D < B.
59.The graph in Figure27 describes the motion of an object moving east along a straight path. Find the acceleration of
theobjectateachofthesetimes:(Level1)
a.duringthefirst5.0minoftravel
b.between5.0minand10.0min
c.between10.0minand15.0min
d.between20.0minand25.0min
SOLUTION:
a. Let east be the positive direction.
b.
c.
d.
ANSWER:
a. Let east be the positive direction.
= 6.0m/min2 east
b. = 0.0m/min2
c. = 2.0m/min2 west
d. = 4.0m/min2 west
Chapter Assessment
Section 2 Motion with Constant Acceleration: Mastering Problems
68.Refer to Figure29to find the magnitude of the displacement during the following time intervals. Round answers to
the nearest meter.
a. t=5.0minandt=10.0min
b. t=10.0minandt=15.0min
c. t=25.0minandt=30.0min
d. t=0.0minandt=25.0min
SOLUTION:
a.
b. Area (15 m/min)(5 min) = 75 m
c.
d.
ANSWER:
a. 88 m
b. 75 m
c. 13 m
d. 288 m
Chapter Assessment: Applying Concepts
78.Explain how you would walk to produce each of the position-time graphs in Figure30.
SOLUTION:
(1) Walk in the positive direction at a constant speed. (2) Walk in the positive direction at an increasing
speed for a short time; keep walking at a moderate speed for twice that amount of time; slow down over
a short time and stop; remain stopped; and turn around and repeat the procedure until the original
position is reached.
ANSWER:
(1) Walk in the positive direction at a constant speed. (2) Walk in the positive direction at an increasing
speed for a short time; keep walking at a moderate speed for twice that amount of time; slow down over
a short time and stop; remain stopped; and turn around and repeat the procedure until the original
position is reached.
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Chapter 3 Practice Problems, Review, and Assessment
