Fluid Dynamics MCQ with answer and solution

Concept

Stagnation Pressure

Formula

P₀ = P + (1/2) × ρ × v² (where P₀ is stagnation pressure, P is static pressure, ρ is fluid density, and v is flow velocity)

Explanation

Stagnation pressure is the total pressure exerted by a fluid when it is brought to a complete stop. At this point, all of the fluid's motion (kinetic energy) is converted into pressure energy, so the flow velocity becomes zero.

Shortcut

Associate stagnation with stoppage: Stagnant water does not move, so at a stagnation point, the fluid comes to a complete stop and its velocity is zero.

Common mistake

Students often confuse stagnation pressure with maximum dynamic pressure and incorrectly choose "Velocity is maximum" (Option A) instead of "Velocity is zero" (Option B), confusing a point of complete fluid stoppage with a point of maximum flow speed.