Question

Calculate the power of a motor in watt which is capable of raising 200kg of water in 5 minutes from a well 120 metre deep

Answer 1

Mass of the water to be raised (m) = 200 kg

Height through which it will be raised (h) = 120 m

Acceleration due to gravity (g) = 9.8 m/s^2

Work done in lifting the water = mgh

Work done = 200 × 9.8 × 120

Work done = 235200 Joules

Power is defined as the rate of doing work.

Hence, the formula for power:

$Power = \frac{Work }{t}$

Time taken (t) = 5 minutes = 300 seconds

$Power = \frac{235200}{300}$

Power = 784 Watts

Hence, the power of the motor is 784 Watts