# Water is pumped out of a well 10m deep by means of a pump rated at 10KW.Find the efficiency of the motor of 4200 kg of water is pumped out every minute.given g=10 m/s squqre

Potential Energy Gained by water in 60 sec= 4200 x 10 x 10 = 4.2 x 10

^{5 }J ( output)

Energy spend by pump( work done by pump)= P x t = 10 x 10

^{3}x 60 = 6x 10

^{5}J ( input)

$Efficiency=\frac{Workoutput}{Workinput}\times 100\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}=\frac{4.2}{6}\times 100\phantom{\rule{0ex}{0ex}}=0.7\times 100\phantom{\rule{0ex}{0ex}}=70\%$

Regards.

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