Q. An engine pumps up 100kg of water through a height of 10 m in 5 s. Given that the efficiency of engine is 60%. If g=$10ms^{- 2},$the power of the engine is
A) 3.3 KW
B) 0.33 KW
C) 0.033KW
D) 33KW
Explanation
(a) Given,
$m = 100kg,\ \ h = 10m,\ \ \ \ t = 5s,\ \ \ \ $
$g = 10ms^{- 2}\ $and $\eta = 60\%$
Power=$\frac{work/time}{\eta} = \frac{100}{60} \times \frac{mgh}{t}$
$= \frac{100}{60} \times \frac{100 \times 10 \times 10}{5}$
$= 3.3 \times 10^{3}W$
$= 3.3kW$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.