A uniform rectangular plate, 40 cm long and 30 cm deep into the paper, hangs in air

Question:

A uniform rectangular plate, 40 cm long and 30 cm deep into the paper, hangs in air from a hinge at its top, 30-cm side. It is struck in its center by a horizontal 3-cmdiameter jet of water moving at 8 m/s. If the gate has a mass of 16 kg, estimate the angle at which the plate will hang from the vertical.

A uniform rectangular plate, 40 cm