Water backs up behind a concrete dam as shown. Leakage under the foundation gives a pressure distribution under the dam as indicated. If the what depth, h is to great, the dame will topple over about its toe (point A). For the dimensions given, determine the maximum water depth for the following widths of l= 20, 30, 40, 50, and 60 ft. Base your analysis on the unit length of the dam. The specific weight of concrete is 150 lb/ft^3.