Note: Give exact answers where possible (for example, 7 is exact but 3.142 is approximate). 9. [12 marks] A conical tank rests on a platform that is 10 metres above a large lake. The circular base of the tank has a radius of 4 metres and the top of the tank is 15 metres above the surface of the lake. How much work must be done to fill the tank with water from the lake if it is to be pumped in through an outlet at the bottom of the tank? Set up your coordinate system so that x = 0 corresponds to the top of the tank and x = 5 corresponds to the base of the tank, which rests on the platform. Use the fact that the density of water is 1000 kg/m and g = 9.8 m/s%