An engine pumps up 100 kg of water through a height of 10m in 5s. Given that the efficiency of the engine is 60%, What is the power of the engine             ( Take $g= 10m{s}^{-2}$)

Power used to pump the water =  $\frac{mgh}{t}=\frac{100\times 10\times 10}{5}$

                                         Power   $=2000W$ 

 $$\begin{gathered} given efficiency = 60\% \\ \Rightarrow 60\% Power of engine=2000 watt \\ \Rightarrow \frac{60}{100}Power of engine=2000 watt \\ \Rightarrow Power of engine=2000\times \frac{100}{60}=3.3kW \end{gathered}$$