A water storage tank 10m×10m×10m has a drainage opening on one of the vertical sides at the bottom which is trapezoidal in shape with a width 2m at the bottom 4 m at the top and 1m height. A gate of same dimension hinged along the top edge is used to close it. What is the minimum horizontal force required to be applied at the bottom to keep the gate closed if the tank has full of water in it? Will there be any change in the force required if the tank is only half full? If yes how much?