(a) Compute the torque developed by an industrial motor whose output is 150 kW at an angular speed of 4000 rev/min. (b) A drum with negligible mass, 0.400 m in diameter, is attached to the motor shaft, and the power output of the motor is used to raise a weight hanging from a rope wrapped around the drum. How heavy a weight can the motor lift at constant speed? (c) At what constant speed will the weight rise?

Solution 35E Step 1: Given data: Power output P = 150 kW Angular speed w = 4000 rev/min × (2 rad/60 sec) w = 418.87 rev/sec Step 2: (a).Power is given by P = w Torque computed is = P/w = 150 × 10 /(418.87 rev/sec) = 358.09 N/m