Question

A CD has to rotate under the readout-laser with a constant linear velocity of 1.25 m/s. If the laser is at a position 3.2 cm from the center of the disk, what are the revolutions per minute (rpms) of the disk?

***Can someone please step me through the problem step by step?***

Answer 1

The angular velocity required, in radians per second, is

w = V/R = 1.25/.032 = 39.1 rad/second

Multiply that by (60 s/min)*(1 rev/2 pi rad)
= 9.55 rpm/(rad/s)
for the rotation speed in rpm