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 12 of 19
- A. √(3P/ρ)
- B. 3Pρ
- C. 3ρ/P
- D. √3ρ/P
Explanation: √3P/ρ: This option represents the correct equation for the root mean square velocity of a gas.
Correct answer: √(3P/ρ)- A. 1 m
- B. 9.8 m
- C. 4.9 m
- D. 19.6 m
Explanation: The speed of efflux through a small hole in a large tank is given by the Torricelli's Law, which is given as:v = √(2gh)where v is the…
Correct answer: 4.9 m- A. 1000 N/m2
- B. 9000 N/m2
- C. 8000 N/m2
- D. 4000 N/m2
Explanation: According to Bernoulli's equation, the pressure difference between two points in a fluid is related to the change in velocity of the fluid…
Correct answer: 4000 N/m2- A. 6πη r2
- B. 6πη/r2
- C. 6πη r
- D. 6πη/r
Explanation: Retarding force=6πη r v. ratio of retarding force to speed (v) would be (6πη r v)/v which equals 6πη r.
Correct answer: 6πη r- A. 5 m/s
- B. 10 m/s
- C. 2 m/s
- D. 50 m/s
Explanation: v2=u2+2as v2=0+2(5)(10) v2=100 v= 10m/s As it is a numerical, it can have only one possible answer.
Correct answer: 10 m/s- A. P + ρv = constant
- B. 2P + ρv2 = constant
- C. P + 1/2ρv2 = constant
- D. 2P + 2ρv2 = constant
Explanation: In a horizontal pipe, the fluid's height does not change, so the gravitational potential energy term in Bernoulli's equation is zero.
Correct answer: P + 1/2ρv2 = constant- A. F = 6πηr2v
- B. F = 6πηrv
- C. F = 6πηrv-1
- D. F = 6π2ηr3v
Explanation: Stokes' law is a law in physics that states that the force that resists a sphere's fall in a viscous fluid is directly proportional to the…
Correct answer: F = 6πηrv228. The product of cross-sectional area of the pipe and the fluid speed at any point along the pipe:
- A. Remains constant
- B. Is zero
- C. Exponentially increases
- D. Exponentially decreases
Explanation: The product of cross-sectional area of the pipe and the velocity of the fluid at any given point along the pipe is constant and is called…
Correct answer: Remains constant- A. 14 m/sec
- B. 10 m/sec
- C. 9.8 m/sec
- D. 20 m/sec
Explanation: Height = h = 10 m Acceleration due to gravity = g = 9.8 m/s² Speed = v = ?
Correct answer: 14 m/sec- A. 0.88 m
- B. 1.1 m
- C. 1.8 m
- D. 8.7 m
Explanation: Pressure P = hρgwhere h is the depth, ρ is the density of the liquid and g is the acceleration of free fall.But,Pressure P = Force / Area…
Correct answer: 0.88 m- A. v
- B. Square root of v
- C. 1/square root of v
- D. v2
Explanation: Formula for viscous drag force is Fs = 6πrηv. Form the given formula it can be seen that keeping r and η constant for a specific object in…
Correct answer: v- A. Remains Constant--- Increases
- B. Decreases _ Increases
- C. Increases _ Decreases
- D. Increases_ Increases
Explanation: Drag is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.You feel the drag force…
Correct answer: Increases_ Increases- A. The coin has not hit the ground
- B. The weight of coin is equal to air resistance
- C. The weight of coin increases as air resistance increases
- D. The weight of coin is more than air resistance
Explanation: In the case of a heavy coin falling a short distance towards the ground, it does not reach terminal velocity because the weight of the…
Correct answer: The weight of coin is more than air resistance234. Density of blood is:
- A. More than water
- B. Less than that of water
- C. Nearly equal to water
- D. 3 times greater than water
Explanation: According to Punjab Text Book, Chapter 6, page 137 (Topic: Blood flow) 1st line: "Blood is an incompressible fluid having a density nearly…
Correct answer: Nearly equal to water- A. A
- B. B
- C. C
- D. D
Explanation: η = 𝐹×𝑑 𝐴×𝑣 Where F is the tangential force, d is the distance between two layers skidding over each other, A is the area and v is the…
Correct answer: D- A. P + ρv = constant
- B. 2P + ρv2 = constant
- C. P + 2ρv2 = constant
- D. 2P + 2ρv2 = constant
Explanation: Since the pipe is horizontal, the average height remains the same so And hence ph=0.
Correct answer: 2P + ρv2 = constant- A. Decreases ... Decreases
- B. Decreases ... Increases
- C. Increases ... Decreases
- D. Increases ... Increases
Explanation: For small objects (such as a bacterium) moving in a denser medium (such as water), the drag force is given by Stokes' law, Fs=6πηrv F s =…
Correct answer: Increases ... Increases- A. kgm2s-1
- B. kgm2s-2
- C. kgm-1s-1
- D. kgms-2
Explanation: The following is the solution:F=krvk=F/rv=ma/rv=kgm-1s-1
Correct answer: kgm-1s-1- A. Velocity
- B. Viscosity of fluid
- C. Density of the body
- D. All of the above
Explanation: The statement "All of the above" means that the acceleration of a falling body in a fluid is influenced by all these factors together, and…
Correct answer: All of the above- A. Pressure at a given point cannot change with time
- B. Velocity at given point cannot change with time
- C. The density cannot change change with time or location
- D. The velocity must be the same everywhere
Explanation: The density cannot change with time or location, since, this directly matches the definition of incompressible flow:𝜌=constantρ=constant…
Correct answer: The density cannot change change with time or location