Question

To maintain a rotor at a uniform angular speed of $200rad{s}^{-1}$, an engine needs to transmit a torque of 180 N m. What is the power required by the engine ? (Note: uniform angular velocity in the absence of friction implies zero torque. In practice, applied torque is needed to counter frictional torque). Assume that the engine is 100% efficient.

Answer 1

Given: The angular speed of the rotor is $200rad/s$.

The torque needed to be transmitted by the engine is $180Nm$.

The power of the rotor required to transmit energy to apply a torque $\tau$ to rotate a motor with angular speed $\omega ,$

$P=\tau \omega$

$=180\times 200W$

$=36kW$