1. A phonograph record has an initial angular speed of 33 rev/min. The record slows to 11
rev/min in 2.0 sec. What is the record’s average angular acceleration during this time
interval. -1.2 rad/sec2
2. A potter’s wheel moves from rest to an angular speed 0.20 rev/sec in 30.0 sec. Assuming
constant angular acceleration, what is its angular acceleration in rad/sec2. 0.042 rad/sec2
3. A drill starts from rest. After 3.20 sec of constant angular acceleration, the drill turns at a
rate of 2628 rad/sec. Find the drill’s angular acceleration. 821 rad/sec2
4. A tire placed on a balancing machine in a service starts from rest and turns through 4.7 revs
in 1.2 secs before reaching its final angular speed. Assuming that the angular acceleration of
the wheel is constant, calculate the wheel’s angular acceleration. 41 rad/sec2
5. The tub within a washer goes into its spin cycle, starting from rest and reaching an angular
speed 34.56 rad/sec in 8.0 seconds. At this point, the lid is opened, and a safety switch turns
off the washer. The tub slows to rest in 12.0 sec. Through how many revolutions does the
tub turn? Assume constant angular acceleration while the machine is starting and stopping.
55 rev
6. To throw a curve ball, a pitcher gives the ball an initial angular speed of 36.0 rad/sec. When
the catcher gloves the ball 0.595 sec later, its angular speed has decreased (due to air
resistance) to 34.2 rad/sec. What is the ball’s angular acceleration, assuming it to be
constant? How many revolutions does the ball make before being caught? -3.03 rad/sec2,
3.33 rev