# A solid disk with a radius of #24 m# and mass of #8 kg# is rotating on a frictionless surface. If #480 W# of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at #18 Hz#?

##### 1 Answer

Mar 1, 2017

#### Explanation:

One way to express torque is by the equation

Given that

#omega=2pif=2pi(18s^-1)=36pi(rad)/s#

So, we have:

#tau=(480W)/(36pi(rad)/s)~~4.2# #N# #m#