A solid disk with a radius of #7 m# and mass of #12 kg# is rotating on a frictionless surface. If #15 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#?

1 Answer
Sep 6, 2017

Answer:

The torque is #=0.20Nm#

Explanation:

The mass of the disc is #m=12kg#

The radius of the disc is #r=7m#

The power #=P# and the torque #=tau# are related by the following equation

#P=tau omega#

where #omega=# the angular velocity

Here,

The power is #P=15W#

The frequency is #f=12Hz#

The angular velocity is #omega=2pif=2*pi*12=24pirads^-1#

Therefore,

the torque is #tau=P/omega=15/(24pi)=0.20Nm#