Answer:
11.52 hp
Explanation:
Givens:
p_1 Â = 15 pisa
p_2 Â = 70 pisa
V_ol=1.5 ft^3/s
Solution: Â
Note: m = p x V_ol (assuming in compressible flow —> p =const) Â
The total change in the system mechanical energy can be calculated as follows, Â
Δ e= (p_2 - p_1 ) /p
The power needed can be calculated as follows
P = W =mΔ e  = p x  V_ol x(p_2 - p_1 ) /p
 = V_ol x (p_2 - p_1 )
 = 44 pisa. ft^3/s
 = 44 x (1 btu/5.404pisa. ft^3) x (1 hp/0.7068btu/s)
 = 11.52 hp