Please help! I haven't really been able to understand this topic :/

What happens in a global convection cell

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."