Question

Water is pumped from a depth of $10\, m$ and delivered through a pipe of cross section $10^{-2}\, m ^{2}$ upto a height of $10\, m$. If it is needed to deliver a volume $0.2\, m ^{3}$ per second the power required will be :

• A. $19.6 \, kW$
• B. $9.8 \, kW$
• C. $39.2\, kW$
• D. $4.9 \, kW$

Answer 1

Answer: (C)

$ P =\frac{W}{t}=\frac{m g h}{t} $
$ t =1 \,s $
$ m =V \rho=0.2 \,m ^{3} \times 1000\, kg / m ^{3} $
$m =200 \,kg $
$ P =\frac{200 \times 9.8 \times(10+10)}{1} $
$ P =200 \times 9.8 \times 20 $
$ P =39200\, W =39.2 \,kW$