The crane lifts a load weighing 5 tons to a height of 10 m. How long does it take to lift the load

The crane lifts a load weighing 5 tons to a height of 10 m. How long does it take to lift the load if the crane’s engine power is 25 kW? Energy losses are insignificant.

Given:

m = 5 tons = 5000 kilograms – the mass of the cargo;

h = 10 meters – the height to which the load is lifted;

g = 10 m / s ^ 2 – acceleration of gravity;

W = 25 kW = 25000 watts – engine power.

According to the condition of the problem, energy losses can be ignored. Then:

The work that needs to be done to lift the load is equal to:

A = F * h = m * g * h = 5000 * 10 * 10 = 500000 Joules.

Then the time for lifting the load will be equal to:

t = A / W = 500000/25000 = 500/25 = 20 seconds.

Answer: it takes 20 seconds to lift the load.