Physics
posted by Sean on .
2. A pool has an area A = 50 m2 and depth h = 2.5 m. The pool is filled with water to the maximum height. An electrical pump is used to empty the pool. There are two pipes coming out the pump: one is submerged into water has a radius r1 = 4 cm the other has a radius r2 = 2.5 cm. Answer the following questions ignoring friction, viscosity, turbulence.
Calculate the net force on the bottom of the pool.
Calculate work done by the pump required to empty the pool in 5 h.
Calculate the speed of the water flow in the submerged pipe.

a. V=A*h = 50*2.5=125 m^3=1.25*10^8 cm^3.
Dw = 1g/cm^3 = 0.001kg/cm^3 = Density of water.
Mass=1.25*10^8cm^30.001kg/cm^3
= 1.25*10^5 kg = Mass of the water.
F=mg = 1.25*10^5kg * 9.8N/kg = 1.225*10^6 N. = Force on bottom.
b. Work = F*d = 1.225*10^6 * 2.5 = =
3.0625*10^6 Joules. 
a.)
P=P initial + pgh
101,000 Pa + (1000)(9.8)(2.5)
P=125500Pa.
P=F/A
125500=F/50
6.3*10^6N