A jet of water issues from a nozzle with a velocity 20 m/s

A jet of water issues from a nozzle with a velocity 20 m/s and it impinges normally on a flat plate moving away from it at 10 m/s. The crosssectional area of the jet is 0.01 m², and the density of water = 1000 kg/m³. The force developed on the plate is

The force developed on the plate,
F_x = ρa(v_j - u)² = 1000 × 0.01(20 10)²
F_x = 1000 N