This calculus 2 video tutorial explains how to find the hydrostatic force on a plane surface submerged in water. This video contains plenty of examples and practice problems of finding the fluid force acting on a vertical submerged plate. Examples include the square, right triangle, isosceles trapezoid, and the semicircle. The weight density of water is 9800 N/m^3 or 62.4 lbs/ft^3.