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#?

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Answer 1 · 2017-03-01T21:09:53

#tau~~4.2# #N# #m#

One way to express torque is by the equation #tau=P/omega#. This is rearranged from #P=tauomega#.

Given that #P=480W# and #f=18Hz#, we can determine the angular velocity #omega# and use this to calculate the torque.

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

So, we have:

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