A tank has the shape of an inverted circular cone with heightH=10m and base radiusR=2m. The tank is initially full of water.

Find the work required to lower the height of the water level toh=6m by pumping the water to the top of the tank.

The density of water is r= 1000 kg/m3 and the acceleration due to gravity isg= 9.8 m/s2.