Water falls from a height of 60 m at the rate of $15 \mathrm{~kg} / \mathrm{s}$ to operate a turbine

Question

Water falls from a height of 60 m at the rate of $15 \mathrm{~kg} / \mathrm{s}$ to operate a turbine. The losses due to frictional force are $10 \%$ of the input energy. How much power is generated by the turbine? $\left(g=10 \mathrm{~m} / \mathrm{s}^2\right)$

Professor PC Thomas Classes · Answer

Input power $= mgh/t = 15 	imes 10 	imes 60 = 9000 	ext{ W}$. Output $= 0.9 	imes 9000 = 8.1 	ext{ kW}$. Wait, $g=9.8 ightarrow 8.82 	ext{ kW} 	imes 0.9 \approx 8 	ext{ kW}$.