Question

A 4-ft-high and 7-ft-wide rectangular plate is submerged vertically in water so that the top is 1 ft below the surface. Express the hydrostatic force against one side of the plate as an integral and evaluate it. (Recall that the weight density of water is 62.5 lb/ft3).

Answer 1

Total depth of the bottom of the plate is 4 + 1 = 5

Force = limit(5,1) 62.5 *7* x * dx

= 437.5. Lim(5,1) x*dx

= 437.5(x^2/2)^5 , 1

= 437.5 x (5^2/2 - 1/2)

= 437.5 x 12

= 5,250 pounds