The cross section of a concrete dam is as shown. For a dam section of unit width, determine
(a) The reaction forces exerted by the ground on the base AB of the dam,
(b) The point of application of the resultant of the reaction forces of part a,
(c) The resultant of the pressure forces exerted by the water on the face BC of the dam. In the following problems, use γ = 62.4 lb/ft3 for the specific weight of fresh water and γc = 150 lb/ft3 for the specific weight of concrete if U.S. customary units are used. With SI units, use ρ = 103 kg/m3 for the density of fresh water and ρc = 2.40 × 103 kg/m3 for the density of concrete. (See the footnote on page 222 for how to determine the specific weight of a material given its density.)

6 m 6 m 18 m 15 m