5. A gas station stores its gasoline in a tank under the ground. The tank is a cylinder standing in upright position. If the radius of the cylinder is 4 ft, its height is 12 ft, and the top is 15 t under the ground, nd the total work needed to pump the gasoline out the tank. Gasoline weighs 42 lb per cubic foot. The tank is full of gasoline. Do the same problem when the tank is half full