Water enters a pump steadily at 180 kPa at a rate of 0.012 m³/s and leaves at 1200 kPa. If the changes in kinetic and potential energies are negligible, the minimum power input to the pump is A)37 kW B)40 kW C)12.2 kW D)52 kW E)74 kW

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Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
V=0.012 "m^3/s"
g=9.81 "m/s^2"
P1=180 "kPa"
P2=1200 "kPa"
"Pump power input is minimum when compression is reversible and thus W=m*v(*P2-P1)=V*(P2-P1)"
W_min=V*(P2-P1) "kPa.m^3/s=kW"
"Some Wrong Solutions with Common Mistakes:"
W1_Win=V*(P2+P1) "Adding pressures instead of subtracting"

Water Enters a Pump Steadily at 180 KPa at a Rate