A solid disk with a radius of #7 m# and mass of #12 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 #15 Hz#?

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Answer 1 · 2018-03-28T06:00:39

The torque is #=1.27Nm#

Apply the equation

#"Power (W)" ="torque(Nm)"xx"angular velocity" (rad s^-1)#

The power is #P=120W#

The frequency is #f=15Hz#

The angular velocity is

#omega=2pif=2xxpixx15=(30pi)rads^-1#

Therefore,

The torque is

#tau=P/omega=120/(30pi)=1.27Nm#