I have a few questions in my Calculus class that I really need help understanding. I don't know much about these work problems; I never took physics. I appreciate any help anyone can give me.

1. Emptying a tank of oil: a spherical tank of radius 8 feet is half full of oil that weighs 50 pounds per cubic foot. Find the work required to pump oil out through a hole in the top of the tank.

2. Work done by an expanding gas: a quantity of gas with an initial volume of 1 cubic foot and a pressure of 500 paid expands to a volume of 2 cubic feet. Find the work done by the gas (Assume that the pressure is inversely proportional to the volume).

Again, thanks!