Fluid Mechanics MCQ Set 4
FLUID MECHANICS MCQ SET 4
Q1. The buoyant force is equal to:
A) Weight of fluid displaced
B) Volume of fluid displaced
C) Density of body
D) None
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Answer: A) Weight of fluid displaced
Explanation: Archimedes’ principle defines buoyant force as the weight of displaced fluid.
Q2. A body will float if its density is:
A) Equal to fluid density
B) Less than fluid density
C) Greater than fluid density
D) Zero
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Answer: B) Less than fluid density
Explanation: A lighter (less dense) body than the fluid will float.
Q3. The metacenter is the point about which:
A) A body starts oscillating when tilted
B) Center of buoyancy moves
C) Center of gravity shifts
D) None
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Answer: A) A body starts oscillating when tilted
Explanation: Metacenter determines stability of a floating body; if above the center of gravity, the body is stable.
Q4. For stable equilibrium of a floating body:
A) Metacenter lies above center of gravity
B) Metacenter lies below center of gravity
C) Both at same level
D) None
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Answer: A) Metacenter lies above center of gravity
Explanation: When metacenter is above the center of gravity, restoring couple brings the body back to equilibrium.
Q5. Streamline flow is characterized by:
A) Random motion
B) Smooth paths
C) Cross mixing
D) Turbulent motion
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Answer: B) Smooth paths
Explanation: In streamline or laminar flow, fluid particles move in smooth, parallel layers.
Q6. The velocity distribution in laminar flow through a circular pipe is:
A) Parabolic
B) Linear
C) Constant
D) Hyperbolic
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Answer: A) Parabolic
Explanation: In laminar flow, the velocity is maximum at the center and minimum at the pipe wall, forming a parabolic profile.
Q7. The head loss due to friction in pipe flow is given by:
A) Bernoulli’s theorem
B) Darcy–Weisbach equation
C) Newton’s law
D) Pascal’s law
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Answer: B) Darcy–Weisbach equation
Q8. The friction factor for laminar flow in a circular pipe is:
A) 16/Re
B) 64/Re
C) 0.316/Re^0.25
D) 4/Re
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Answer: B) 64/Re
Explanation: For laminar flow (Re < 2000), the friction factor is 64 divided by Reynolds number.
Q9. In turbulent flow, head loss is proportional to:
A) Velocity
B) Velocity squared
C) Square root of velocity
D) None
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Answer: B) Velocity squared
Explanation: In turbulent flow, head loss ∝ V² due to eddy motion and increased energy dissipation.
Q10. The hydraulic gradient line (HGL) represents:
A) Total head
B) Pressure head + Datum head
C) Velocity head
D) None
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Answer: B) Pressure head + Datum head
Explanation: HGL shows the sum of pressure head and potential head at various points along the pipe.