Answer: Decreases with increasing temperature.
- A Decreases with increasing temperature
- B Increases with increasing temperature
- C Is independent of temperature
- D Equals surface tension
Correct answer: A. Decreases with increasing temperature
Explanation: As temperature increases, liquid viscosity decreases (molecular bonds weaken). Gas viscosity, however, increases with temperature (more molecular collisions).
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.