Question

A pump is required to lift 1000 kg of water per minute from a well of depth 10 m and eject it with a speed of $10{ms}^{-1}$. The horse-power of the engine needed is : (assume $g=10m{s}^{-2}$)

• A. $3.25$
• B. $4.33$
• C. $5.35$
• D. $2.35$

Answer 1

The correct option is A $3.25$

Given,

$m=1000kg$

$t=1min=60sec$

$h=10m$

$v=10m/s$

$g=10m/s^2$

Power, $P=\frac{mgh+\frac{1}{2}m{v}^2}{t}$

$P=\frac{1000\times 10\times 10+\frac{1}{2}\times 1000\times 10\times 10}{60}$

$P=\frac{100000+50000}{60}=\frac{150000}{60}=2500W$

As we know that, $1horse-power=746Watt$

$1W=\frac{1}{746}horse-power$

$2500W=\frac{2500}{746}=3.25HP$

The correct option is A.