Chapter 7 Problems
1,
2
,
3
= straightforward, intermediate,
challenging
= full solution available in
Student
Solutions Manual/Study Guide
= coached solution with
hints available at
www.cp7e.com
= biomedical application
Section 7.1
Angular Speed and Angular
Acceleration
1.
The tires on a new compact car have
a diameter of 2.0 ft and are warranted for 60
000 miles. (a) Determine the angle (in
radians) through which one of these tires
will rotate during the warranty period. (b)
How many revolutions of the tire are
equivalent to your answer in (a)?
2.
A wheel has a radius of 4.1 m. How
far (path length) does a point on the
circumference travel if the wheel is rotated
through angles of 30°, 30 rad, and 30 rev,
respectively?
3.
Find the angular speed of Earth
about the Sun in radians per second and
degrees per day.
4.
A potter’s wheel moves from rest to
an angular speed of 0.20 rev/s in 30 s. Find
its angular acceleration in radians per
second per second.
Section 7.2
Rotational Motion under
Constant Angular Acceleration
Section 7.3
Relations between Angular
and Linear Quantities
5.
A dentist’s drill starts from rest. After
3.20 s of constant angular acceleration, it
turns at a rate of 2.51 × 10
4
rev/min. (a) Find
the drill’s angular acceleration. (b)
Determine the angle (in radians) through
which the drill rotates during this period.
6.
A centrifuge in a medical laboratory
rotates at an angular speed of 3 600
rev/min. When switched off, it rotates
through 50.0 revolutions before coming to
rest. Find the constant angular acceleration
of the centrifuge.
7.
A machine part rotates at an angular
speed of 0.60 rad/s; its speed is then
increased to 2.2 rad/s at an angular
acceleration of 0.70 rad/s
2
. Find the angle
through which the part rotates before
reaching this final speed.
8.
A tire placed on a balancing machine
in a service station starts from rest and
turns through 4.7 revolutions in 1.2 s before
reaching its final angular speed. Calculate
its angular acceleration.
9.
The diameters of the
main rotor and tail
rotor of a singleengine helicopter are 7.60
m and 1.02 m, respectively. The respective
rotational speeds are 450 rev/min and 4 138
rev/min. Calculate the speeds of the tips of
both rotors. Compare these speeds with the
speed of sound, 343 m/s.
10.
The tub of a washer goes into its
spindry cycle, starting from rest and
reaching an angular speed of 5.0 rev/s in 8.0
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View Full Documents. At this point, the person doing the
laundry opens the lid, and a safety switch
turns off the washer. The tub slows to rest
in 12.0 s. Through how many revolutions
does the tub turn during the entire 20s
interval? Assume constant angular
acceleration while it is starting and
stopping.
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 Fall '10
 Jay
 Force, Friction, Mass, Black hole

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