A spherical tank with a radius of 1m is buried with the top of the tank 3m below ground level. The tank is full of fuel oil with density 800kg/m. Set up (but you do NOT need to evaluate) a definite integral that gives the work done in pumping all of the oil out if the tank at the ground level. (The gravitational constant is 9.8m/s). (Note: Sketch the tank and put the x and y axis at a strategic place)