Question

A 10 H.P. motor pumps out water from a well of depth 20m and fills a water tank of volume 22380 litres at a height of 10m from the ground. the running time of the motor to fill the empty water tank is $(g = 10ms^{- 2}$)

• A. 5 minutes
• B. 10 minutes
• C. 15 minutes
• D. 20 minutes

Answer 1

Answer: (C)

15 minutes

Answer 2

Volume of water to raise = 22380 l = 22380×10^–3m³

$P = \frac { m g h } { t } = \frac { V \rho g h } { t }$ ⇒ $t = \frac { V \rho g h } { P }$

t$= \frac { 22380 \times 10 ^ { - 3 } \times 10 ^ { 3 } \times 10 \times 10 } { 10 \times 746 } = 15$min