Q7.15 To maintain a rotor at a uniform angular speed of , an engine needs to
transmit a torque of . 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 efficient.
The relation between power and torque is given by :
or
Hence the required power is 36 KW.