The hemispherical tank is full of water. Given that water weighs 62.5 lb/ft^3, find the work required to pump?

Question

the water out of the tank. Radius= 5 feet

Answer 1

Technically you could just siphon the water out and not do any pump work.

But if you mount a pump on top of the tank, the work required to pump it out can be found by :

1. Calculate the total weight of the water in the tank = 2/3*Pi*r^3*62.5 = 16,362.5 pounds

2. Calculate the center of mass of the hemisphere from the circular top of the tank = 3*r/8 = 1.875 feet

Then the work required is 1.875 feet *16,362.5 pounds = 30679.6875 foot - pounds

Answer 2

You may need to give a little more detail. Pump from where? To where? And where is the pump? A pump power requirement is dependent on the 'foot of head' which is an elevation and a density of the fluid. It can be converted to power but the lay out is important. http://www.engineeringtoolbox.com/centrifugal-pumps-d_54.html this site may help search pump power