# A solid disk with a radius of #3 m# and mass of #4 kg# is rotating on a frictionless surface. If #120 W# of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at #8 Hz#?

##### 1 Answer

Nov 19, 2016

The torque applied is 2.38 N-m.

#### Explanation:

This goes very simple, Power is the product of the torque and angular velocity, similar to

So here angular acceleration comes with

Calculating the angular velocity with given frequency we get,

Now the above power equation becomes

Substituting the given values we get,