a tank, shaped like a cone has height 7 meters and base radius 3 meters long. it is placed so that the circular part is upward. it is full of water, and we have to pump it all out by a pipe that is always leveled at the surface of the water. assume that a cubic meter of water weighs 10 000 n , i.e. the density of water is 10000 n m 3 . how much work does it require to pump all water out of the tank? enter the exact value of your answer.