Impact of a jet of water

Mar 2018
Hi, I would like some help with the following problem:
"A jet of water issues from a nozzle, of diameter h_1=0,102 m (and depth b=1 m), at a speed U_1=2,02 m/s. The jet strikes a flat plate of mass M=2,05 kg, as shown in figure, and it breaks into two jets of equal speed and diameter h_2=0,122 m and h_3=0,102 m. Determine the speed at which the water leaves the plate, U. Kowing that α=30° and that the volume in transition is V=5,05 L, find the components F_x and F_y of the total force that should be applied on the plate to maintain it in equilibrium". (Solutions are U=0.9198, F_x=28.48 and F_y= -389.7).

To answer the first question, I took the jet as my control volume and I applied the momentum conservation equation on it:
So: U=(U_1h_1)/(h_2+h_3)= 0.9198
My doubts concern the second question: I tried to apply again the momentum equation now on the whole system, but I think this is not the right way to solve it...
Thank you in advance for the help.


Jun 2016
To get the force, you need the rate of change of momentum.

You say
the volume in transition is V=5,05 L
Do you mean 5.05 liters per second?

remember 1 litre of water masses 1 kg.
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