A jet of water of density ρ of cross-section S with a horizontal velocity v hits
the blades of the water wheel, after the impact flowing down the blade. Find
the power of this water engine at the angular velocity of rotation of the wheel
ω. Radius of the R wheel. The number of blades is sufficiently large, so that
the effect of the jet can be considered continuous, ignoring its changes at the
entrance of the blade to the jet and at the exit from it.