A solid disk with a radius of 4 m and mass of 6 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 12 Hz?

1 Answer
Feb 9, 2017

tau=(960)/(24pi)~~12.73N*m

Explanation:

We are told we have a rotating spinning coin.

http://www.mariowiki.com/coinhttp://www.mariowiki.com/coin

Step 1. Gather the information that you know and need

  • Mass of disk: "mass"=m=6" kg"
  • Radius of disk: "radius"=r=4" m"
  • Power applied to increase rotation: P=960" W"
  • Frequency: f=12" Hz"
  • Torque required: ??

Step 2. Determine the formula using the above givens

  • P is the power applied, P=tau omega
  • Therefore, torque is tau=P"/"omega
  • Angular speed, omega=f*2pi=12*2pi=24pi

Step 3. Plug your knows into the formula for torque

tau=(960)/(24pi)~~12.73N*m