Answer: 9.8 N.
- A 9.8 N
- B 1 N
- C 98 N
- D 10 N
Correct answer: A. 9.8 N
Explanation: F<sub>b</sub> = ρ V g = 1000 × 10⁻³ × 9.8 = 9.8 N. This is also the weight of 1 litre of water.
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.