Force exerted normal to the plate

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foo9008
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Homework Statement


A jet of water , 50mm diameter , with a velocity of 18m/s , strikes a flat plate inclined at 25 degree to the axis of jet as shown in figure, Determine the normal force , P exerted on the plate when plate is stationary .

Homework Equations

The Attempt at a Solution


Hand-drawn sketch of a jet striking an inclined flat plate, with angle labels 25° and 65° marked between the jet direction, the plate and the plate's normal.

in the diagram attached , i found that the angle between the water velocity make an angle of 65 degree to the normal of the plate ,
so my ans is F = ρA(v)(v cos theta) = 1000(pi)( [(50x10^-3) / 2 ] ^2 ) (18^2)(cos 65) = 278.7 N , is my working correct ? i don't have the ans
 
Attachments
  • Diagram of a water jet from a nozzle striking a flat plate inclined at 25 degrees to the jet axis, with the normal force P shown as an arrow acting on the plate's underside.
    l4.png
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Last edited:
foo9008 said:

Homework Statement


A jet of water , 50mm diameter , with a velocity of 18m/s , strikes a flat plate inclined at 25 degree to the axis of jet as shown in figure, Determine the normal force , P exerted on the plate when plate is stationary .

Homework Equations

The Attempt at a Solution


Hand-drawn sketch of a rectangular plate crossed by two lines meeting at its center, with angles labeled 65° and 25° and a right-angle mark where a line meets the plate.

in the diagram attached , i found that the angle between the water velocity make an angle of 65 degree to the normal of the plate ,
so my ans is F = ρA(v)(v cos theta) = 1000(pi)( [(50x10^-3) / 2 ] ^2 ) (18^2)(cos 65) = 278.7 N , is my working correct ? i don't have the ans
Your algebraic expression looks right but I don't get same answer (about 4% less). Check your arithmetic.
 
haruspex said:
Your algebraic expression looks right but I don't get same answer (about 4% less). Check your arithmetic.
my ans is 268.8N