Question:
The power of a motor pump is $2 \mathrm{~kW}$. How much water per minute the pump can raise to a height of $10 \mathrm{~m}$ ? (Given $g=10 \mathrm{~ms}^{-2}$ ).
Solution:
$P=2 \mathrm{~kW}=2000 \mathrm{~W}, h=10 \mathrm{~m}, t=80 \mathrm{~s}$
$\mathrm{P}=\frac{m g h}{t}$
$\therefore m=\frac{\mathrm{P} t}{g h}=\frac{2000 \times 60}{10 \times 10}=1200 \mathrm{~kg}$