A solid disk with a radius of #6 m# and mass of #9 kg# is rotating on a frictionless surface. If #120 W# of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at #8 Hz#?

1 Answer
Mar 29, 2017

Answer:

The torque is #=2.39Nm#

Explanation:

mass of disc #=9kg#

radius of disc #=6m#

The power is related to the torque by the equation

#P=tau *omega#

#P=120W#

Frequency of rotation is #f=8Hz#

#omega=f*2pi#

angular velocity, #omega=8*2pi rads^-1#

torque, #tau=P/omega#

#=120/(16pi)=2.39Nm#