Question

A rectangular plate 12 ft long and 8 ft wide is submerged vertically with the longer edge in the surface of the water. Find the force on one side of the plate.

Answer 1

$F=pS,$

$p=\rho g h,$

$S=hb,$

$F=\rho g h^2b,$

$1~ft=0.3048~m,$

$F=1000\cdot 10\cdot 8^2\cdot 12\cdot 0.3048^3=213~kN.$