A solid disk with a radius of $12 m$ and mass of $5 kg$ is rotating on a frictionless surface. If $450 W$ of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at $7 Hz$ ?

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Answer 1 · 2017-10-28T05:55:34

The torque is $=10.23Nm$

The mass of the disc is $m=5kg$

The radius of the disc is $r=12m$

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 $P=450W$

The frequency is $f=7Hz$

The angular velocity is $omega=2pif=2*pi*7=(14pi)rads^-1$

Therefore,

the torque is $tau=P/omega=450/(14pi)=10.23Nm$

A solid disk with a radius of 12 m12 m and mass of 5 kg5 kg is rotating on a frictionless surface. If 450 W450 W of power is used to increase the disk's rate of rotation, what torque is applied when the disk is rotating at 7 Hz7 Hz?