A solid disk with a radius of $6 m$ and mass of $2 kg$ 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 · 2017-07-23T12:27:12

The torque is $=1.27Nm$

The mass of the disc is $m=2 kg$

The radius of the disc is $r=6m$

The power and the torque are related by the formula

$P=tau omega$

The angular velocity is $omega=2pif=2pi*15=30pirads^-1$

The power is $P=120W$

Therefore,

The torque is

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

A solid disk with a radius of 6 m6 m and mass of 2 kg2 kg is rotating on a frictionless surface. If 120 W120 W of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at 15 Hz15 Hz?