# Flat vertical plate moving of jet - Ishwaranand

## Force on the flat vertical plate moving in the direction of the jet

Fig. shows a jet of water punching a flat vertical plate moving with a similar velocity away from the jet. Image Source ~ Crafted With ©Ishwaranand - 2020 ~ Image by ©Ishwaranand
Fig. This jet striking flat vertical moving plate
Let
v = Velocity of the jet (absolute)
u = Velocity of the flat plate.
Hence, the relative velocity of per jet with respect before the plate
= (v- u)
Mass about water striking each plate /sec
= ρ x Area of jet x Velocity with which jet strikes the plate
= ρa x [v - u]

Force exerted by the jet on the moving plate in the direction of the jet,

Fx  = Mass of water striking per sec x [Initial velocity with which water strikes - Final velocity]
= ρa (v - u) [(v – u) - 0]
( Final velocity in the direction of jet is zero)
= ρa (v - u)^2
• In this case, the work will be done by the jet on the plate, as the plate is moving.
• For the stationary plates, the work done is zero.
• Work was done per second by the jet on the plate
= Forces x (Distance in each direction of force / Times)
= Fx X u
= ρa(v - u)^2 x u