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An electric motor drives a pump that raises 1,000 litres of water each minute, to a tank 20m above ground level. Calculate the power that the motor must provide if the pump is only:

50% efficient: 

80% efficient: 

 Mar 30, 2021

Best Answer 

 #1
avatar+31287 
+2

Similar to the other water pumping problem

 

Mass of 1000 liters of water = 1000 kg

 

F = mg   =   1000 kg * 9.81 m/s2 = 9810 N

W = F * d = 9810 N * 20 m = 196200 j

Power = work /time = 196200j / 60 sec = 3270 watts

 

50% efficient means 50% is wasted..... it will take twice as much power to pump the water =   2 * 3270 = 6540 watts

 

80% efficient  :    3270 / .8 = 4087.5 watts

 Mar 30, 2021
 #1
avatar+31287 
+2
Best Answer

Similar to the other water pumping problem

 

Mass of 1000 liters of water = 1000 kg

 

F = mg   =   1000 kg * 9.81 m/s2 = 9810 N

W = F * d = 9810 N * 20 m = 196200 j

Power = work /time = 196200j / 60 sec = 3270 watts

 

50% efficient means 50% is wasted..... it will take twice as much power to pump the water =   2 * 3270 = 6540 watts

 

80% efficient  :    3270 / .8 = 4087.5 watts

ElectricPavlov Mar 30, 2021

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