FE Exam Fluid Mechanics - 3.4 - Practice Problem - Continuity and Impulse-Momentum Principle

[@bishalpokharel5360]

Why did you negleted P1A1? Coz they are negligible when exposed to atmosphere?

[@carultch]

P1*A1 is a force that is resisted by the constraint that holds the nozzle in place, which is out of the picture of the question asked. We are interested in the force that holds the impinged plate in place.

[@josea.serrano-perez3544]

Is it ok to use here the equation for jet propulsion, it would be the same Fx = Qp(V2), why not use this directly?

[@CollegeFluidMechanics]

As long as you are careful about the inherent assumptions for the jet propulsion equation (pressure forces are negligible is one one assumption), you sure can use it.

[@Keko881000]

Can this problem be solved by applying conservation of Energy between two points ( Discharge and Impact) Points, Then F = PA ??

[@CollegeFluidMechanics]

Good question: unfortunately, that will not work. You can not multiple static pressure with cross sectional area to find the force exerted by a flow (due to the existence of fluid momentum). You can use that formula for static cases safely, though