3. The tank shown in the Figure is filled with water and has a 4cm diameter plug at the bottom on the right. There is a manometer connected to the tank on the left-hand side, filled with Mercury. All fluids are at 20C. The safety plug will pop out if the hydrostatic force on it is 25N. The density of the water and Mercury are w=998kg/m3 and m=13568kg/m3, respectively. The gravitational acceleration is g=9.81m/s2. a) When the plug is about to pop out, what is the distance from the centroid of the plug to the free surface of water, hc ? b) When the plug is about to pop out, what will be the height, h, of the mercury in the manometer