Water backs up behind a concrete dam as shown in Fig.P2.60. Leakage under the foundation...

Water backs up behind a concrete dam as shown in Fig.P2.60. Leakage under the foundation gives a pressure distribution under the dam as indicated. If the water depth, h, is too great, the dam will topple over about its toe (point A). For the dimensions given, determine the maximum water depth for the following widths of the dam: l=20,30,40,50, and 60 ft. Base your analysis on a unit length of the dam. The specific weight of the concrete is 150 lb/ft³.