Physics Physics Fluid Dynamics 2 — Questions and Answers
Question 1: Bernoulli's principle relates which quantities in steady fluid flow?
- Pressure, velocity, and height (Correct answer)
- Temperature, volume, and pressure
- Mass, velocity, and force
- Density, viscosity, and flow rate
Correct answer: Pressure, velocity, and height
Bernoulli's principle states that the sum of pressure, kinetic energy per unit volume, and potential energy per unit volume is constant along a streamline.
Question 2: According to Bernoulli's equation, what happens to pressure when fluid velocity increases?
- Pressure decreases (Correct answer)
- Pressure increases
- Pressure stays the same
- Pressure doubles
Correct answer: Pressure decreases
Bernoulli's equation shows an inverse relationship between fluid velocity and pressure — as velocity increases, pressure decreases.
Question 3: What is the Reynolds number used to determine in fluid mechanics?
- Whether flow is laminar or turbulent (Correct answer)
- The speed of fluid flow
- The pressure of a fluid
- The viscosity of a fluid
Correct answer: Whether flow is laminar or turbulent
The Reynolds number is a dimensionless quantity used to predict whether fluid flow will be laminar or turbulent.
Question 4: What does the continuity equation A₁v₁ = A₂v₂ predict when a pipe narrows?
- Fluid speeds up (Correct answer)
- Fluid slows down
- Fluid pressure increases
- Fluid temperature decreases
Correct answer: Fluid speeds up
When a pipe narrows (A decreases), the fluid velocity must increase to maintain constant mass flow rate, as required by the continuity equation.
Question 5: What is terminal velocity?
- Constant speed when drag equals gravitational force (Correct answer)
- Maximum possible speed in a vacuum
- Speed at which turbulence begins
- Initial speed of a falling object
Correct answer: Constant speed when drag equals gravitational force
Terminal velocity is the constant speed a falling object reaches when the drag force exactly equals the gravitational force, resulting in zero net acceleration.
Question 6: In laminar flow, fluid particles move in:
- Parallel layers without mixing (Correct answer)
- Random chaotic directions
- Circular vortex patterns
- Opposing countercurrent directions
Correct answer: Parallel layers without mixing
In laminar flow, fluid particles travel in smooth, parallel layers with no disruption between the layers, also called streamline flow.
Physics Physics Fluid Dynamics 2
Bernoulli's principle relates which quantities in steady fluid flow?