If a paddle of area, A, is submerged in a river of water-velocity, v, and (assumed constant) water pressure, P, the paddle at an angle, m, what is the force exerted on the paddle by the moving water of the river?
the paddle is being held still from a bridge...
the angle, m, is at 0 when the paddle is held perpendicular to the direction of the velocity of the water.
this is not homework - for my own learning. Thank you.
the paddle is being held still from a bridge...
the angle, m, is at 0 when the paddle is held perpendicular to the direction of the velocity of the water.
this is not homework - for my own learning. Thank you.
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Every second a volume of water Av, of mass ρAv, where ρ is the water density, impacts the paddle and imparts ρAv^2 units of momentum to it, well actually only the sinm component at right angles to it exerts the force (the cosm component glides over its surface). So the rate of change of the paddle's momentum, which is the force on it, is ρAsinmv^2.