#### Answer

(a) $187.5 lb/ft^{2} $
(b) $1875 lb$
(c) $562.5 lb$

#### Work Step by Step

Weight density of water is $\delta = 62.5 lb / ft^{3}$
(a) $P = \delta d \approx (62.5 lb/ft^{3})(3ft) = 187.5 lb/ft^{2} $
(b) $F = PA \approx (187.5 lb/ft^{2})(5ft)(2ft) = 1875 lb$
(c) $F = \int^{3}_{0} \delta x 2dx \approx (62.5)(2) \int^{3}_{0} x dx = 125 [\frac{1}{2} x^{2}]^{3}_{0} = 562.5 lb$