Applications of Integration

I have the more difficult time with word problems. Can someone help guide me through a couple of them? More than wanting to find what the answer is, if someone could help me understand the why and how of the problems I would appreciate it.

The diameter of a circular pool is 24 m, the sides

are 5 m high, and the depth of the water is 4 m. How

much work is required to pump all of the water out

over the side?

Ok so far I've drawn a diagram which is a cylinder with radius of 12 and height of 5 meters. I've gone ahead and added the water height of 4 meters as well. Now I know I need to find how much work will be involved in getting all the water out. How would I go about this. (Speechless)