Answer: N s m-2.
- A N s m-2
- B kg m s-1
- C N m-1
- D Pa m
Correct answer: A. N s m-2
Explanation: Viscosity has units of pascal-second, and 1 Pa s = 1 N s m-2.
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.