To maintain a rotor at a uniform angular speed of 200 rad s ^ -1 … - Vidyadip

Question

To maintain a rotor at a uniform angular speed of $200 rad s ^{-1}$, 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 $10 \%$ efficient.

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Answer

Given :
$\begin{aligned} \omega & =200 rad / s ^2 \\ \tau & =180 Nm \\ P & =? \\ P & =\tau \omega \text { using the relation } \\ & =180 \times 200=36,000 W \\ & =36 kW\end{aligned}$

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