A square plate of uniform thickness has a side length of 25 cm that hangs vertically from hinges at its top edge, as shown in Figure P5.31. When a horizontal jet strikes the plate at its center, the...

A square plate of uniform thickness has a side length of 25 cm that hangs vertically from hinges at its top edge, as shown in Figure P5.31. When a horizontal jet strikes the plate at its center, the plate is deflected and comes to rest at an angle of 30° to the vertical. The jet is 2 cm in diameter and has a velocity of 8 m/s. Calculate the mass of the plate. What force should be applied at the lower edge of the plate to maintain its vertical position?