Answer: P0 + ρgh.
- A P0 + ρgh
- B ρgh
- C P0 - ρgh
- D ρg/h
Correct answer: A. P0 + ρgh
Explanation: Total pressure = atmospheric pressure P0 plus the pressure due to the fluid column: P = P0 + ρgh.
Since the same volume of fluid must pass every cross-section per second (continuity), the fluid speeds up where the pipe narrows; Bernoulli's equation then says this faster-moving fluid has lower pressure - the principle behind a venturi meter and an aircraft wing's lift.
Concept context
Pressure, buoyancy, Bernoulli equation, viscosity, and surface tension.