COLLEGE PHYSICS FREEDMAN CHAPTER 28
PRACTICE QUESTIONS AND DETAILED
SOLUTIONS
◉ A wheel, originally rotating at 126 rad/s undergoes a constant
angular deceleration of 5.00 rad/s2. What is its angular speed after
it has turned through an angle of 628 radians?
A) 15 rad/s
B) 19 rad/s
C) 98 rad/s
D) 121 rad/s
E) 150 rad/s.
Answer: C) 98 rad/s
◉ A wheel turns through an angle of 188 radians in 8.0 s; and its
angular speed at the end of the period is 44 rad/s. If the angular
acceleration is constant, what was the angular speed of the wheel at
the beginning of the 8.0 s interval?
A) 3.0 rad/s
B) 7.0 rad/s
C) 9.1 rad/s
D) 23.5 rad/s
,E) 32.5 rad/s.
Answer: A) 3.0 rad/s
◉ A spinning disc rotating at 130 rev/min slows and stops 31 s later.
How many revolutions did the disc make during this time?
A) 34
B) 67
C) 8.4
D) 17
E) 4.2.
Answer: A) 34
◉ A 1.0-m roulette wheel reaches a maximum angular speed of 18
rad/s before it begins decelerating. After reaching this maximum
angular speed, it turns through 35 revolutions (220 rad) before it
stops. How long did it take the wheel to stop after reaching its
maximum angular speed?
A) 12 s
B) 48 s
C) 3.7 s
D) 8.8 s
E) 24 s.
Answer: E) 24 s
,◉ What is the tangential speed of a lug nut on a wheel of a car if the
lug nut is located 0.114 m from the axis of rotation; and the wheel is
rotating at 6.53 rev/sec?
A) 0.745 m/s
B) 1.49 m/s
C) 2.98 m/s
D) 4.68 m/s
E) 9.36 m/s.
Answer: D) 4.68 m/s
◉ A 0.254-m diameter circular saw blade rotates at a constant
angular speed of 117 rad/s. What is the tangential speed of the tip of
a saw tooth at the edge of the blade?
A) 29.7 m/s
B) 14.9 m/s
C) 9.46 m/s
D) 7.45 m/s
E) 2.17 m/s.
Answer: B) 14.9 m/s
, ◉ What is the tangential speed of Nairobi, Kenya, a city near the
equator? The earth makes one revolution every 23.93 h and has an
equatorial radius of 6380 km.
A) 74.0 m/s
B) 116 m/s
C) 148 m/s
D) 232 m/s
E) 465 m/s.
Answer: E) 465 m/s
◉ On an amusement park ride, passengers are seated in a horizontal
circle of radius 7.5 m. The seats begin from rest and are uniformly
accelerated for 21 seconds to a maximum rotational speed of 1.4
rad/s.
What is the tangential acceleration of the passengers during the first
21 s of the ride?
A) 0.067 m/s2
B) 0.50 m/s2
C) 1.4 m/s2
D) 7.5 m/s2
E) 11 m/s2.
Answer: B) 0.50 m/s2
PRACTICE QUESTIONS AND DETAILED
SOLUTIONS
◉ A wheel, originally rotating at 126 rad/s undergoes a constant
angular deceleration of 5.00 rad/s2. What is its angular speed after
it has turned through an angle of 628 radians?
A) 15 rad/s
B) 19 rad/s
C) 98 rad/s
D) 121 rad/s
E) 150 rad/s.
Answer: C) 98 rad/s
◉ A wheel turns through an angle of 188 radians in 8.0 s; and its
angular speed at the end of the period is 44 rad/s. If the angular
acceleration is constant, what was the angular speed of the wheel at
the beginning of the 8.0 s interval?
A) 3.0 rad/s
B) 7.0 rad/s
C) 9.1 rad/s
D) 23.5 rad/s
,E) 32.5 rad/s.
Answer: A) 3.0 rad/s
◉ A spinning disc rotating at 130 rev/min slows and stops 31 s later.
How many revolutions did the disc make during this time?
A) 34
B) 67
C) 8.4
D) 17
E) 4.2.
Answer: A) 34
◉ A 1.0-m roulette wheel reaches a maximum angular speed of 18
rad/s before it begins decelerating. After reaching this maximum
angular speed, it turns through 35 revolutions (220 rad) before it
stops. How long did it take the wheel to stop after reaching its
maximum angular speed?
A) 12 s
B) 48 s
C) 3.7 s
D) 8.8 s
E) 24 s.
Answer: E) 24 s
,◉ What is the tangential speed of a lug nut on a wheel of a car if the
lug nut is located 0.114 m from the axis of rotation; and the wheel is
rotating at 6.53 rev/sec?
A) 0.745 m/s
B) 1.49 m/s
C) 2.98 m/s
D) 4.68 m/s
E) 9.36 m/s.
Answer: D) 4.68 m/s
◉ A 0.254-m diameter circular saw blade rotates at a constant
angular speed of 117 rad/s. What is the tangential speed of the tip of
a saw tooth at the edge of the blade?
A) 29.7 m/s
B) 14.9 m/s
C) 9.46 m/s
D) 7.45 m/s
E) 2.17 m/s.
Answer: B) 14.9 m/s
, ◉ What is the tangential speed of Nairobi, Kenya, a city near the
equator? The earth makes one revolution every 23.93 h and has an
equatorial radius of 6380 km.
A) 74.0 m/s
B) 116 m/s
C) 148 m/s
D) 232 m/s
E) 465 m/s.
Answer: E) 465 m/s
◉ On an amusement park ride, passengers are seated in a horizontal
circle of radius 7.5 m. The seats begin from rest and are uniformly
accelerated for 21 seconds to a maximum rotational speed of 1.4
rad/s.
What is the tangential acceleration of the passengers during the first
21 s of the ride?
A) 0.067 m/s2
B) 0.50 m/s2
C) 1.4 m/s2
D) 7.5 m/s2
E) 11 m/s2.
Answer: B) 0.50 m/s2
