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"If the velocity of impact of the jet is V feet per second, its velocity in the same direction after striking the plate will be zero, a definite force will be exerted on that plate, equal to the force necessary to impart a velocity of V feet in one second to the mass of water in the jet." —Derr, 1911

Water Jet Deflected 90 Degrees Measuring Force

"If the velocity of impact of the jet is V feet per second, its velocity in the same direction after…