A solid disk with a radius of #21 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#?

1 Answer
Apr 3, 2017

Answer:

The torque is #=4.24Nm#

Explanation:

mass of disc #=8kg#

radius of disc #=21m#

The power is related to the torque by the equation

#P=tau *omega#

#P=480W#

Frequency of rotation is #f=18Hz#

#omega=f*2pi#

angular velocity, #omega=18*2pi rads^-1#

torque, #tau=P/omega#

#=480/(36pi)=4.24Nm#