The rectangular gate in Figure is hinged at A and separates water in the reservoir from th...

The rectangular gate in Figure is hinged at A and separates water in the reservoir from the tail water tunnel. If the uniformly thick gate has a dimension of 2 m X 3 m and weighs 20 kN, what is the maximum height h for which the gate will stay closed? (Hint: Assume the water level h does not rise above the hinge.)

Figure