A solid disk with a radius of #9 m# and mass of #4 kg# is rotating on a frictionless surface. If #750 W# of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at #4 Hz#?

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Answer 1 · 2017-06-23T05:55:23

The torque is #=29.8Nm#

The mass of the disc is #m=4 kg#

The radius of the disc is #r=9m#

The power and the torque are related by the formula

#P=tau omega#

The angular velocity is #omega=2pif=2pi*2=8pirads^-1#

The power is #P=750W#

Therefore,

The torque is

#tau=P/omega=750/(8pi)=29.8Nm#