Question

Component of velocity in direction of jet is -VCosθ. What does ‘θ’ indicate?

(a) Angle made by jet

(b) Angle made by jet and outlet tip

(c) Angle made by jet and inlet tip

(d) Tangent angle

This question was addressed to me in an international level competition.

Question is from Force Exerted by a Jet on a Stationary Curved Plate in portion Impact of Jets and Jet Propulsion of Fluid Mechanics

Answer 1

Right option is (c) Angle made by jet and inlet tip

For explanation: Component of velocity in direction of jet is -VCosθ. The negative sign indicates the that the taken velocity at the outlet is opposite to the jet of water coming out from the nozzle. ‘θ’ indicates the angle made by jet and inlet tip of the curved plate.