10. Reservoir-Pump System. What horsepower must the 80%-efficiency-pump be required to pump 50 gpm (gallon per minute) water (1.94-slug/ /ft3 density; 2.2105-psf.s viscosity) to the higher reservoir (h= 200ft )? Pipe characteristics are: length (total) =10 miles (52,800ft), diameter =6in, and relative roughness =0.006. Loss coefficients are: 2.5 (pipe entrance), 3.2 (pipe exit), 5.4 (valve 1), 6.8 (valve 2 ), and 0.7 (elbow, each). [1 gallon =77/576ft3;1 hp=550ftbf/s;g=32.2ft/s2.] Ans. 3.5hp