The uniform plate is used to control the upstream water level to maintain constant depth. Determine the required height of water on the downstream side so that seepage will not occur. This hydrostatic forces on a plane surface example problem will be solved using the Pressure Prism method to analyze the hydrostatic pressure distribution on the planar surface, and turn these forces on submerged surfaces into rotational moments about the hinge. Master Fluid Mechanics with my full course playlist: TIMECODES 0:00 Free Body Diagram 4:45 Equilibrium Equation 7:01 Pressure Prisms 14:11 Solve and Check Final Answer