A solid disk with a radius of $5 m$ and mass of $4 kg$ 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 $5 Hz$ ?

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Answer 1 · 2017-07-12T06:30:04

The torque is $=0.48Nm$

The mass of the disc is $m=4 kg$

The radius of the disc is $r=5m$

The power and the torque are related by the formula

$P=tau omega$

The angular velocity is $omega=2pif=2pi*5=10pirads^-1$

The power is $P=15W$

Therefore,

The torque is

$tau=P/omega=15/(10pi)=0.48Nm$

A solid disk with a radius of 5 m5 m and mass of 4 kg4 kg is rotating on a frictionless surface. If 15 W15 W of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at 5 Hz5 Hz?