A solid disk with a radius of #4 m# and mass of #3 kg# is rotating on a frictionless surface. If #72 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#?

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Answer 1 · 2017-05-02T08:38:55

The torque is #=0.95Nm#

Mass of disc #=3kg#

Radius of disc #=4m#

The power is related to the torque by the equation

#P=tau *omega#

#P=72W#

Frequency of rotation is #f=12Hz#

#omega=f*2pi#

angular velocity, #omega=12*2pi rads^-1#

torque, #tau=P/omega#

#=72/(24pi)=0.95Nm#