Section B: Answer ALL the Questions. Each question carries 20 marks. 6. The water in a tank is pressurized by air and the pressure is measured by a manometer as shown in Figure 3. The tank is located on a mountain at an 1400m where the atmospheric pressure is 85.6kPa. Take the densities of wat mercury to be 1000kg/m3,850kg/m3 and 13,600kgm3, respectively. If h1,h2 : 0.1m,0.2m and 0.35m, respectively, (a) derive an equation that relates the air pressure in the tank, Pt, in terms of Patm (atmospheric pressure), density of water, uasur,densityof mercury, maxaur,h1,h2 and h3. (b) Then, determine the pressure caused by: (i) water (ii) oil and (iii) mercury (c) Hence, determine the air pressure in the tank, Pi