Free Fluid Dynamics MCQs with Answers
363 Fluid Dynamics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Fluid flow is described through speed, pressure and density, including steady flow and the equation of continuity for conserving mass. Bernoulli's equation relates pressure, speed and height, while fluid drag and terminal velocity explain why a falling object eventually moves at constant speed when drag balances its weight.
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Read the Fluid Dynamics notesFree MDCAT chapter notes with key terms363 questions · page 18 of 19
- A. Bernoulli's equation
- B. Venturi meter
- C. Equation of motion
- D. Equation of continuity
Explanation: The correct answer is D) Equation of continuity, as it directly expresses the conservation of mass in fluid flow.
Correct answer: Equation of continuity- A. Increases
- B. Decreases
- C. Remains constant
- D. Both B and C
Explanation: Drag force is a resistive force, which can only increase as forward force increases.
Correct answer: Decreases- A. r = √qvt / 2ρg
- B. r2 = 9ηvt / ρg
- C. r2 = 9ηvt / 2ρg
- D. r = 9ηvt / 2ρg
Explanation: Explanation If ρ is the density of the droplets then its volune can be expressed as: V = 4/3 πr³As, ρ = m / VSo, ρ = m / (4/3 πr³ρ) m =…
Correct answer: r2 = 9ηvt / 2ρg- A. 500 Km min-1
- B. 500 Km sec-1
- C. 1000 Km h-1
- D. 500 Km h-1
Explanation: Explanation:The lifting of a bullet train above the rails due to magnetic fields reduces friction, allowing the train to reach higher…
Correct answer: 500 Km h-1- A. F = 6πηrv
- B. F = (4/3)πr3ρg
- C. F = 6πηr2ρ
- D. F = 2gr2ρ/9η
Explanation: Stokes' Law describes the drag force experienced by a small spherical object moving through a fluid at a low velocity.
Correct answer: F = 6πηrv- A. Pascal's Law
- B. Hooke's Law
- C. Boyle's Law
- D. Charles's Law
Explanation: Explanation:By Pascal's law, pressure on each side of the container and everywhere in the container is the same provided the density of…
Correct answer: Pascal's Law- A. Mass
- B. Density
- C. Pressure
- D. Force
Explanation: In an incompressible fluid, particles have a constant density. An incompressible fluid is defined as one whose density does not change on…
Correct answer: Density- A. vt = 4gr2ρ / 9η
- B. vt = 9ηr2ρ / 4g
- C. vt = 2gr2ρ / 9η
- D. vt = 9ηr2ρ / 2g
Explanation: Explanation:Using strokes law, 6πηrvt = mg Where, m = 4/3 πr³ρComparing both equations, we get: r² = 9ηvt /2ρg vt = 2gr²ρ / 9η
Correct answer: vt = 2gr2ρ / 9η- A. Torrielll's effect
- B. Bernoulli's effect
- C. Venturis effect
- D. Doppler effect
Explanation: Bernoulli's principle states that as the speed of a fluid increases, the pressure exerted by the fluid decreases.
Correct answer: Bernoulli's effect350. Water flows through a constriction in horizontal pipe as it enters the constriction, the water's:
- A. Speed increases and pressure remains constant
- B. Speed increases and pressure increase
- C. Speed increases and pressure decreases
- D. Speed decreases and pressure Increases
Explanation: We know that the volume flow rate (Avt) is constant, with V/v = A, we know that Area is directionally proportional to velocity.
Correct answer: Speed increases and pressure decreases- A. 2.5m/s
- B. 24m/s
- C. 4.44m/s
- D. Cannot be calculated unless the area of the hole is given
Explanation: The problem can be solved using Torricelli's Theorem, which states that the speed of efflux, v, of a fluid under the force of gravity…
Correct answer: 24m/s- A. A1/A2
- B. A2/A1
- C. (A1 + A2)/(V1 + V2)
- D. (V1 + V2)/(A1 + A2)
Explanation: According to the continuity equation for incompressible fluids, the flow rate (product of cross-sectional area and velocity) is constant.
Correct answer: A2/A1- A. 2.8m/s
- B. 3.7m/s
- C. 6.6m/s
- D. 8.8m/s
Explanation: The problem can be solved using the continuity equation, which states that A1V1 = A2V2, where A is the cross-sectional area of the pipe.
Correct answer: 2.8m/s- A. Velocity
- B. Viscosity of fluid
- C. Density of the body
- D. All of above
Explanation: When a body falls through a fluid, it experiences a resistance force due to the viscosity of the fluid.
Correct answer: All of above- A. Spherical shape
- B. Oblong shape
- C. Rectangular shape
- D. Curve shape
Explanation: Stokes' Law holds true for bodies that have a spherical shape. It describes the motion of a small spherical particle through a viscous…
Correct answer: Spherical shape- A. Weight in water
- B. Weight in liquid
- C. Weight in air
- D. Volume
Explanation: According to the Archimedes principle, if an object is immersed in a fluid, it experiences an apparent loss of weight which is equal to…
Correct answer: Volume- A. Will be pulled towards each other
- B. Will drift apart from each other
- C. Will have no effect on each other
- D. Will experience random motion
Explanation: As the speed of water between the ships is greater than outside them, pressure between them gets reduced, and pressure outside is greater…
Correct answer: Will be pulled towards each other- A. 4.9 x 10^-3 m3/s
- B. 4.9 m3/s
- C. 7.0 m3/s
- D. 49 m3/s
Explanation: We are asked to find the volume rate of flow in this question. With the radius 1.5cm (0.015m) we can find the cross-sectional area of the…
Correct answer: 4.9 x 10^-3 m3/s- A. Zero
- B. Minimum but not zero
- C. Large
- D. Peripheral
Explanation: b) Minimum but not zeroThis option suggests that the velocity of the liquid in contact with the containing vessel is the minimum but not…
Correct answer: Minimum but not zero- A. The air resistence just balances the force of gravity
- B. The force of gravity ois constant for all drops
- C. All drops fall from the same height
- D. The drops are small so force of gravity is negligible for them
Explanation: Terminal velocity, the steady speed achieved by an object freely falling through a gas or liquidLet's go into the imagination A raindrop…
Correct answer: The air resistence just balances the force of gravity