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 14 of 19
- A. α√h
- B. α h
- C. α (1/h)
- D. Almost independent of h
Explanation: As a small drop of water falls through the air, it experiences forces due to gravity and air resistance.
Correct answer: Almost independent of h- A. Area decreases
- B. Area increases
- C. Velocity remains same
- D. Area remains same
Explanation: The correct answer is that the area decreases. As the water falls from the tap, it accelerates under gravity, increasing its velocity.
Correct answer: Area decreases- A. Rotational flow
- B. Irrotational flow
- C. Laminar flow
- D. None of these
Explanation: Viscous forces, which result from the internal friction between layers of fluid in motion, are present in many types of fluid flows.
Correct answer: None of these- A. More
- B. Less
- C. Not affected by change in viscosity
- D. Unpredictable
Explanation: The correct answer is that the thickness of the boundary layer is More when the viscosity of the fluid is higher.
Correct answer: More- A. 60 ft/s
- B. 30 ft/s
- C. 40 ft/s
- D. 20 ft/s
Explanation: According to the principle of continuity for incompressible fluid flow, the flow rate (area × velocity) must be conserved across both…
Correct answer: 20 ft/s- A. 256 m/s
- B. 345 m/s
- C. 123 m/s
- D. 1.59 m/s
Explanation: To find the speed of water at the outlet, first calculate the volumetric flow rate:Volumetric flow rate = Mass flow rate / Density = 30 kg…
Correct answer: 1.59 m/s- A. Law of conservation of mass
- B. Law of conservation of energy
- C. Law of conservation of power
- D. Law of conservation of volume
Explanation: Bernoulli's equation is derived from the principle of the conservation of energy.
Correct answer: Law of conservation of energy- A. Pressure of fluid with speed of fluid
- B. Pressure to volume
- C. Pressure to elevation
- D. Both pressure with speed and pressure to elevation are correct
Explanation: Bernoulli's equation is an expression of the conservation of energy for flowing fluids.
Correct answer: Both pressure with speed and pressure to elevation are correct- A. The velocity of the liquid is greater, so the pressure will be greater
- B. When the velocity of the liquid is less, the pressure will be high, and vice versa
- C. When the velocity of the liquid is less, the pressure will be less
- D. All are correct
Explanation: The equation η + 1/2ρv² + ρgh = constant is a representation of Bernoulli's principle, which states that in a streamline flow, the sum of…
Correct answer: When the velocity of the liquid is less, the pressure will be high, and vice versa- A. Vt√2
- B. Vt
- C. 4Vt
- D. 2Vt
Explanation: The terminal velocity of a raindrop is governed by the balance between gravitational force and drag force.
Correct answer: 4Vt- A. 1.5 cm/s
- B. 6 cm/s
- C. 24 cm/s
- D. 32 cm/s
Explanation: When eight smaller spherical drops merge into one larger drop, the volume of the larger drop is the sum of the volumes of the smaller…
Correct answer: 24 cm/s- A. Increases
- B. Decreases
- C. Same
- D. Different
Explanation: The equation of continuity states that A1V1 = A2V2, where A is the cross-sectional area and V is the fluid velocity.
Correct answer: Decreases- A. Equation of continuity
- B. Bernoulli's equation
- C. Light equation
- D. Speed equation
Explanation: The Venturi effect is a reduction in fluid pressure that occurs when a fluid flows through a constricted section of a pipe.
Correct answer: Bernoulli's equation- A. Depends on the angle and orientation of the plane
- B. Independent of angle and orientation
- C. Insufficient information is provided to determine
- D. All of the above
Explanation: The pressure difference between the lower and upper surfaces of an airplane is influenced by the angle of attack and the airplane's…
Correct answer: Depends on the angle and orientation of the plane- A. 2V
- B. VC
- C. V/2
- D. 4V
Explanation: The principle of continuity for incompressible fluids states that the mass flow rate must remain constant from one cross-section of a pipe…
Correct answer: 4V- A. Laminar flow
- B. Turbulent flow
- C. Streamline flow
- D. Both A and C
Explanation: Laminar flow and streamline flow represent the same type of smooth, orderly movement of a fluid.
Correct answer: Both A and C- A. Heavy object will reach the ground first
- B. Light object will reach the ground first
- C. Heavy object will fall faster
- D. Both will reach the ground at the same time
Explanation: In a vacuum, there is no air resistance to affect the rate at which objects fall.
Correct answer: Both will reach the ground at the same time- A. The terminal velocity will be very large
- B. The terminal velocity will be very small
- C. No terminal velocity
- D. Constant terminal velocity
Explanation: In a vacuum, a falling body experiences no air resistance, allowing it to continually accelerate under the influence of gravity.
Correct answer: No terminal velocity- A. 0
- B. g
- C. 6πηrV-mg
- D. a = 6πηrV/m - g
Explanation: The correct answer is a = 6πηrV/m - g. When a body falls through a viscous medium, it experiences a drag force in addition to…
Correct answer: a = 6πηrV/m - g- A. g
- B. a > g
- C. 0
- D. constant
Explanation: The correct answer is 0. When a body moves with constant speed, its velocity does not change over time.
Correct answer: 0