Answer:
The answer is given below
Explanation:
Things provided in the statement:
Pressure P1 = 120 kPa and P2 = 5.6 MP or 5600 kPa
Power, W = 7 kW
Elevation difference = ∆z = 10 m
Mass of flow = mË™
So potential energy changes may be significant
Specific volume of water V= 0.001 m³/kg
Now putting the values in the formula
Power, W = m˙  x V (P1 - P2) + m˙ x g x ∆z
       7 = m˙  x 0.001 (5600 - 120 ) + m˙ x 9.8 x 10 x (1 kJ/kg/ 1000 m^2/s^2)
       7 = m˙ x 5.48 + m˙ x 0.098
       7 = m ˙x 5.38
      m˙ = 7/5.38
     So mass flow m˙  =  1.301 kJ/s