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 15 of 19
- A. 10 N
- B. 100 N
- C. 0
- D. 20 N
Explanation: Since the object is moving at a constant speed, the net force acting on it must be zero.
Correct answer: 100 N- A. Vt
- B. 4Vt
- C. 9Vt
- D. 2Vt
Explanation: The terminal speed of a droplet is proportional to the square of its radius (Vt ∝ r2).
Correct answer: 4Vt- A. Gravitational force
- B. Electromagnetic
- C. Cohesive force
- D. None
Explanation: Viscosity is a measure of a fluid's resistance to flow, and it arises from the cohesive forces between the molecules of the fluid.
Correct answer: Cohesive force- A. Increases
- B. Decreases
- C. Remains constant
- D. None of these
Explanation: The viscosity of gases increases with an increase in temperature. This is because, at higher temperatures, gas molecules have more kinetic…
Correct answer: Increases- A. 8m3/sec
- B. 6m3/sec
- C. 4m3/sec
- D. None of these
Explanation: To find the volumetric flow rate, use the formula: Flow rate = Cross-sectional area × Velocity.
Correct answer: 4m3/sec- A. P+3/2ρV2
- B. P-3/2ρV2
- C. P+1/2ρV2
- D. P-1/2ρV2
Explanation: According to Bernoulli's principle, for an incompressible, non-viscous fluid flowing at a constant height, an increase in fluid speed…
Correct answer: P-3/2ρV2- A. t/√3
- B. t/3
- C. 3t
- D. √3t
Explanation: According to Torricelli's theorem, the time to empty a container is proportional to the square root of the height of the fluid.
Correct answer: t/√3- A. ρAv2
- B. 1/2ρAv2
- C. 1/2ρv2
- D. None
Explanation: The correct answer is ρAv2. According to Bernoulli's principle, the lift force on an aerofoil is due to the pressure difference created by…
Correct answer: ρAv2- A. 1:2
- B. 2:1
- C. 4:1
- D. 1:4
Explanation: Terminal velocity of a spherical object falling through a fluid is proportional to the square of its radius.
Correct answer: 1:4- A. 32 m/s
- B. 16 m/s
- C. 8 m/s
- D. 64 m/s
Explanation: The terminal velocity of a droplet is proportional to the square root of its radius.
Correct answer: 8 m/s- A. √4gh
- B. √2v
- C. √2gh/2
- D. √2gh
Explanation: The speed of efflux through an orifice at the bottom of a tank is determined by Torricelli's Law, which is derived from Bernoulli's…
Correct answer: √2gh- A. 0.5 T
- B. 0.707 T
- C. 0.88 T
- D. 0.4 T
Explanation: The correct answer is 0.707 T. This is because the process of evacuating a tank often follows an exponential decay pattern, as described…
Correct answer: 0.707 T- A. Attract
- B. Repel
- C. Remain same
- D. None
Explanation: When two boats move parallel to each other in water, the water between them flows faster than the water outside them.
Correct answer: Attract294. Mass flow rate is
- A. AVt
- B. AV
- C. ρAV
- D. ρAVt
Explanation: The mass flow rate is defined as the mass of fluid passing through a cross-sectional area per unit time.
Correct answer: ρAV- A. a = 0
- B. g = 0
- C. Both
- D. None
Explanation: At terminal velocity, the force of gravity acting on the body is balanced by the drag force, resulting in no net force.
Correct answer: a = 0- A. Double
- B. Half
- C. Remain same
- D. Quadrupled
Explanation: According to Poiseuille's Law, the flow rate through a pipe is inversely proportional to the length of the pipe.
Correct answer: Half- A. The ball sinks
- B. The ball rises
- C. The ball remains immersed at its former depth
- D. It oscillates
Explanation: The correct answer is Option C: The ball remains immersed at its former depth.
Correct answer: The ball remains immersed at its former depth- A. 3:2
- B. 4:9
- C. 9:4
- D. 27:8
Explanation: The terminal velocity of a spherical object falling through a fluid is proportional to the square root of its volume.
Correct answer: 27:8- A. All points
- B. Inner points
- C. Outer points
- D. None of these
Explanation: The correct answer is All points. In streamline flow, Bernoulli's principle states that the total energy (which includes potential energy…
Correct answer: All points- A. Viscosity
- B. Surface tension
- C. Pressure
- D. Archimedes' upward thrust
Explanation: The correct answer is Pressure. In a fluid, pressure is the result of the weight of the fluid acting on a given area, which is directly…
Correct answer: Pressure