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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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Terminal VelocityFluid DragFluid FlowEquation of ContinuityBernoulli's Equation
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363 questions · page 17 of 19

321. A parachutist is falling constant (terminal) velocity. Which statement is not correct?

  • A. Gravitational potential energy is converted into kinetic energy of the air
  • B. Gravitational potential energy is converted into kinetic energy of the parachutist
  • C. Gravitational potential energy is converted into thermal energy of the air
  • D. Gravitational potential energy is converted into thermal energy of the parachutist

Explanation: At terminal velocity, the parachutist is falling at a constant speed, meaning there is no net conversion of gravitational potential energy…

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Correct answer: Gravitational potential energy is converted into kinetic energy of the parachutist

322. Water flows through a constriction in horizontal pipe as it enters constriction, water's:

  • A. Speed increases and pressure remains constant
  • B. Speed increases and pressure increases
  • C. Speed increases and pressure decreases
  • D. Speed decreases and pressure increases

Explanation: In fluid dynamics, especially in incompressible flow through a pipe, Bernoulli's principle applies.

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Correct answer: Speed increases and pressure decreases

323. Rain drops falling from sky reach the ground with:

  • A. Constant acceleration
  • B. Constant terminal velocity
  • C. Acceleration greater than g
  • D. Variable acceleration

Explanation: The correct answer is Constant terminal velocity. When rain drops fall, they initially accelerate due to gravity.

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Correct answer: Constant terminal velocity

324. The ebb and flow of the tides----- explained by Newton.

  • A. are
  • B. was
  • C. were
  • D. is

Explanation: The correct answer is option D) is because it aligns with the singular subject "The ebb and flow of the tides." In English grammar, it is…

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Correct answer: is

325. Spot the error.For our marketing department, we need a MBA who has had the experience of working in the same field.

  • A. for
  • B. a
  • C. has had
  • D. the

Explanation: This is incorrect. It should be "an" because "MBA" starts with a vowel sound.

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Correct answer: a

326. Choose the correct option.

  • A. That was a big eye-opener for both I and she.
  • B. That was a big eye-opener for both her and me.
  • C. That was a big eye opener for both her and I.
  • D. That was a big eye-opener for both she and me.

Explanation: This option is correct. "Her" and "me" are both object pronouns, which are correct here since they are the objects of the preposition "for."

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Correct answer: That was a big eye-opener for both her and me.

327. Each sentence below has a blank indicating that something has been omitted. Choose the word that best fits in with the meaning of the sentence as a whole.The cruel animal owners were known to treat their dogs in a _ manner.

  • A. Compatible
  • B. Congruent
  • C. Chimerical
  • D. Barbaric

Explanation: The word that best fits in the blank is"barbaric."Barbaric implies extremely cruel or brutal behavior, which is consistent with the idea…

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Correct answer: Barbaric

328. Directions: Read the following information and give answer.A, B. C, D and E are five friends. B is elder to E, but not as tall as C. C is younger to A. and is taller to D and E. A is taller to D, but younger than E. D is elder to A but is shortest in the group.If F, another friend, is taller than C, how many of them will be between F and E according to their height?

  • A. Three
  • B. One
  • C. Two
  • D. None of these

Explanation: To solve the question, we must first arrange the friends by height using the provided clues: D is the shortest, A is taller than D, C is…

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Correct answer: Two

329. In the following question, two statements numbered I and II are given. There may be cause and effect relationship between the two statements. These two statements may be the effect of the same cause or independent causes. These statements may be independent causes without saving any relationship. Read both the statements in question and mark your answer as:A. If statement I is the cause and statement II is its effect;B. If statement II is the cause and statement, I is its effect;C. If both the statements I and II are independent causes;D. If both the statements I and II are effects of independent causes;E. If both the statements I and II are effects of some common causes;I. She got admitted into one of the top colleges.II. She worked day and night to achieve a good score in the entrance exam.

  • A. A. If statement I is the cause and statement II is its effect;
  • B. B. If statement II is the cause and statement I is its effect;
  • C. C. If both the statements I and II are independent causes;
  • D. D. If both the statements I and II are effects of independent causes;
  • E. E. If both the statements I and II are effects of some common cause;

Explanation: The correct answer is Option B: Statement II is the cause and Statement I is its effect.

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Correct answer: B. If statement II is the cause and statement I is its effect;

330. If each particle of a fluid passing through a point follows the same path, then this flow is called

  • A. Ideal flow.
  • B. Normal flow.
  • C. Turbulent flow.
  • D. Streamline flow.

Explanation: The correct answer is streamline flow. In streamline or laminar flow, fluid particles move along well-defined paths or streamlines, and…

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Correct answer: Streamline flow.

331. If the different layers of a fluid offer no resistance over each other, then the fluid will be a/ an

  • A. Ideal fluid
  • B. Viscous fluid
  • C. Newtonian fluid
  • D. Non-viscous fluid

Explanation: The correct answer is ideal fluid. An ideal fluid is a theoretical fluid that is incompressible and non-viscous, meaning it has no…

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Correct answer: Ideal fluid

332. In fluid dynamics, if every particle passing through a given point undergoes in an irregular pattern and fluctuation, then this type of flow is called a

  • A. Steady flow
  • B. Laminar flow
  • C. Turbulent flow
  • D. Streamline flow

Explanation: The correct answer is 'turbulent flow.' This type of flow is characterized by chaotic changes in pressure and velocity, leading to…

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Correct answer: Turbulent flow

333. All of the following are the factors on which terminal velocity of a falling object depends EXCEPT

  • A. Mass of the object.
  • B. Velocity of the object.
  • C. Cross-sectional area of the object.
  • D. Gravitational acceleration of the object.

Explanation: The correct answer is Option B:Velocity of the object.Terminal velocity is the constant speed achieved when the force of gravity is…

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Correct answer: Velocity of the object.

334. All of the following are the factors of which terminal velocity of a falling object depends EXCEPT

  • A. Mass of the object
  • B. Velocity of the object
  • C. Cross-sectional area of the object
  • D. Gravitational acceleration of the object

Explanation: The correct answer is velocity of the object because terminal velocity is a specific constant speed achieved when the forces of gravity…

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Correct answer: Velocity of the object

335. If a water droplet falls from a height in air,its terminal velocity will be attained when the drag force is

  • A. Twice the weight of the droplet
  • B. Thrice the weight of the droplet
  • C. Half of the weight of the droplet
  • D. Equal to the weight of the droplet

Explanation: At terminal velocity, a falling object moves at a constant speed because the net force acting on it is zero.

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Correct answer: Equal to the weight of the droplet

336. When an object moves with a terminal velocity, then the acceleration of the object will

  • A. -9.8 m/s2
  • B. 0 m/s2
  • C. 4.9 m/s2
  • D. 9.8 m/s2

Explanation: When an object moves with a terminal velocity, the net force acting on it becomes zero because the drag force equals the gravitational…

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Correct answer: 0 m/s2

337. The object that easily attains the terminal velocity is a

  • A. Rain drop.
  • B. Cricket ball.
  • C. Falling apple from a tree.
  • D. Falling stone from some height.

Explanation: The correct answer is Option D:falling stone from some height.A stone is dense and compact, which means it has a high weight-to-surface…

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Correct answer: Falling stone from some height.

338. Torricelli's theorem be written as:

  • A. v2 = √ 2g (h1 - h2)
  • B. v2 = √ g (h2 - h1)
  • C. v2 = √ 2g (h2 - h1)
  • D. v2 = √ g (h1 - h2)

Explanation: Explanation:Torricelli's theorem states that the velocity (v) of a liquid flowing out of an orifice at the bottom of a container is equal…

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Correct answer: v2 = √ 2g (h1 - h2)

339. In Bernoulli's equation, the term 1/2 v2 is called:

  • A. K.E. per unit volume
  • B. K.E.
  • C. K.E. per unit area
  • D. K.E. per unit length

Explanation: Bernoulli's equation formula is a relation between the pressure, kinetic energy, and gravitational potential energy of a fluid in a…

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Correct answer: K.E. per unit volume

340. A pipe varies uniformly in diameter from 2m to 4m. An incompressible fluid enters the pipe with velocity 16 m/s. What is velocity of fluid when it leaves the pipe?

  • A. 64 m/s
  • B. 32 m/s
  • C. 8 m/s
  • D. 4 m/s

Explanation: Given that,d1=2md2=4mV1=16m/sV2=𝑥From flow rate,A1V1 =A2V2(πr2)1V1=(πr2)2V2(d12/4)V1=(d22/4)V2By substituting the given values,𝑥= V2 =…

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Correct answer: 4 m/s
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