Question

A dvd drive has a maximum speed of 7200rpm if a dvd has diameter of 12 cm what is linear speed

Answer 1

The equation relating angular speed and linear speed is:

v = r w

where,

v = linear speed

r = radius = 0.5 diameter = 6 cm

w = angular speed in rad

 

First let us convert w in rad / minute:

w = 7200 rev / min * (2π rad / 1 rev)

w = 45,238.93 rad / min

 

So linear speed is therefore calculated as:

v = (6 cm) (45,238.93 rad / min)

v = 271,433.60 cm / min

or expressed in other units:

v = 4,523.90 cm / s = 45.24 m / s = 2,714.34 m / min