A solid disk with a radius of #3 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#?

1 Answer
Apr 21, 2017

The torque is #=29.84Nm#

Explanation:

Mass of disc #=4kg#

Radius of disc #=3m#

The power is related to the torque by the equation

#P=tau *omega#

#P=750W#

Frequency of rotation is #f=4Hz#

#omega=f*2pi#

angular velocity, #omega=4*2pi rads^-1#

torque, #tau=P/omega#

#=750/(8pi)=29.84Nm#