Rotation of a disk?

Question

A solid disk rotating at 33rpm is slowed by friction, stopping after 10 seconds. Find the angular aceleration in rad/s²

Answer 1

By definition
a=w/t
a- angular acceleration (usually alpha) in rad / sec^2
w - angular velocity in rad /sec
t - time
w=2pi (rpm)/(60 sec)
a=2pi (rpm)/[(60 sec)(t)]
a=2 x (3.14159..) x 33/(60 x 10)
a=0.345 rad/sec
I hope it helps