A hoist operated by an electric motor has a mass of 500 kg. It raises a load of 300 kg vertically at a steady speed of 0.2 m/s. Frictional resistance can be taken to be constant at 1200 N. What is the power required?
Total mass = m = 800 kg
Weight = 800 × 9.81
= 7848 N
Total force = 7848 + 1200
= 9048 N
Power = force × speed
= 9048 × 0.2
= 1810 W
= 1.81 kW