Find the work done in pumping the water over the rim of a tank that is 40 feet long and has a semicircular end of radius 10 feet if the tank is filled to a depth of 4 feet

Answer 1

This web site shows how to find the area of the cross-section. Using that, the volume is 40*area. The weight is density * volume.

Then you can either integrate to find the work, or just see how high the center of mass has to be lifted, and work = weight * distance.

http://mathworld.wolfram.com/CircularSegment.html