A solid disk with a radius of 2 m and mass of 2 kg is rotating on a frictionless surface. If 960 W of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at 9 Hz?

1 Answer
Aug 10, 2017

The torque is =16.98Nm

Explanation:

The mass of the disc is m=2kg

The radius of the disc is r=2m

The power P and the torque tau are related by the following equation

P=tau omega

where omega= the angular velocity

Here,

The power is P=960W

The frequency is f=9Hz

The angular velocity is omega=2pif=2*pi*9=18pirads^-1

Therefore,

the torque is tau=P/omega=960/(18pi)=16.98Nm