Question

A crane 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 ms − 1. Assume resistance to be constant at 1200 N. What is the power required to raise the load?

Answer 1

Here, you are given too much information and you don't need all. You can use a simple formula for power to calculate. You don't need the masses of crane or object.

P = F.v

here, F is the resistance force, F= 1200N
v is the velocity at which the mass is moving, v = 0.2 m/s

So power = 1200 × 0.2 = 240 W