A Brake Pad Is Used to Give a Normal Force

Multiple Choice

A brake pad is used to give a normal force of 150 N to the outer surface of a 0.25 kg spinning disk, in order to slow it down from 250 rpm to rest. The disk's radius is 0.25 m. If the coefficient of friction between the pad and the disk is 0.45, how much time is required for the disk to slow from 250 rpm to rest?

A) 0.19 ms
B) 0.55 ms
C) 2.4 ms
D) 12 ms