Question

Calculate the power of an electric engine which can lift 20000kg of coal per hour from a
mine 180m depth.

Answer 1

Answer:

Explanation:

I take a ton as a metric ton or tonne equal to 1000 kg weight.

Mass of coal transported to a height of 180 meters in one hour

           = 20 metric tons = 20,000 kg

Change in the potential energy of coal : m g h

        = 20,000 kg * 9.81 m/sec² * 180 m = 35,316 kJoules

Power supplied by the electric engine = Energy supplied / time duration 

            = 35,316 kJ / 3600 sec = 9.81 kW

 Power = 10 kW if g is taken as 10 m/sec².

Hope it helps/