Fluid Dynamics Actual Exam 2026
Complete Questions and Verified
Answers with Detailed Rationales 100%
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Graded
1. The density of a fluid is defined as:
A. Mass per unit volume
B. Force per unit area
C. Volume per unit mass
D. Weight per unit pressure
Answer: A. Mass per unit volume
Rationale: Density is defined as the mass contained within a unit volume of a
substance. It is commonly expressed as kg/m³ in SI units.
2. Dynamic viscosity measures a fluid's resistance to:
A. Compression
B. Shear deformation
C. Temperature change
D. Pressure increase
Answer: B. Shear deformation
Rationale: Dynamic viscosity quantifies the resistance of a fluid to shear motion
between adjacent layers.
3. The SI unit of dynamic viscosity is:
,A. Pascal
B. Newton
C. Pascal-second
D. Joule
Answer: C. Pascal-second
Rationale: Dynamic viscosity has units of Pa·s, which represent the relationship
between shear stress and velocity gradient.
4. A Newtonian fluid is one in which:
A. Density remains constant
B. Shear stress is proportional to velocity gradient
C. Pressure remains constant
D. Temperature remains constant
Answer: B. Shear stress is proportional to velocity gradient
Rationale: Newtonian fluids obey Newton’s law of viscosity, where shear stress
varies linearly with velocity gradient.
5. The specific gravity of a fluid is the ratio of its density to:
A. Air density
B. Absolute pressure
C. Density of water at standard conditions
D. Dynamic viscosity
Answer: C. Density of water at standard conditions
Rationale: Specific gravity compares a fluid’s density to the density of water.
6. Pressure in a stationary fluid increases with:
A. Decreasing depth
B. Increasing viscosity
,C. Increasing depth below the surface
D. Increasing velocity
Answer: C. Increasing depth below the surface
Rationale: Hydrostatic pressure increases because the weight of the fluid above
contributes to pressure at greater depths.
7. The pressure at a point in a static fluid acts:
A. Only upward
B. Only downward
C. Equally in all directions
D. Only horizontally
Answer: C. Equally in all directions
Rationale: Pascal’s law states that pressure at a point in a fluid at rest is
transmitted equally in all directions.
8. The hydrostatic pressure equation is:
A. P = ρV
B. P = ρgh
C. P = μV
D. P = Q/A
Answer: B. P = ρgh
Rationale: Hydrostatic pressure depends on fluid density, gravitational
acceleration, and depth.
9. The buoyant force on an immersed object equals:
A. Object weight
B. Fluid pressure
, C. Weight of displaced fluid
D. Fluid density only
Answer: C. Weight of displaced fluid
Rationale: Archimedes’ principle states that buoyant force equals the weight of
displaced fluid.
10. The continuity equation is based on conservation of:
A. Momentum
B. Energy
C. Mass
D. Entropy
Answer: C. Mass
Rationale: The continuity equation represents conservation of mass in a fluid
system.
11. For incompressible steady flow, the continuity equation becomes:
A. P₁ = P₂
B. A₁V₁ = A₂V₂
C. T₁ = T₂
D. F = ma
Answer: B. A₁V₁ = A₂V₂
Rationale: For incompressible flow, volume flow rate is conserved, so area and
velocity are inversely related.
12. The velocity of a fluid generally increases when flowing through a:
A. Larger area passage
B. Smaller area passage
Complete Questions and Verified
Answers with Detailed Rationales 100%
Correct Grade A Pass Guaranteed - A+
Graded
1. The density of a fluid is defined as:
A. Mass per unit volume
B. Force per unit area
C. Volume per unit mass
D. Weight per unit pressure
Answer: A. Mass per unit volume
Rationale: Density is defined as the mass contained within a unit volume of a
substance. It is commonly expressed as kg/m³ in SI units.
2. Dynamic viscosity measures a fluid's resistance to:
A. Compression
B. Shear deformation
C. Temperature change
D. Pressure increase
Answer: B. Shear deformation
Rationale: Dynamic viscosity quantifies the resistance of a fluid to shear motion
between adjacent layers.
3. The SI unit of dynamic viscosity is:
,A. Pascal
B. Newton
C. Pascal-second
D. Joule
Answer: C. Pascal-second
Rationale: Dynamic viscosity has units of Pa·s, which represent the relationship
between shear stress and velocity gradient.
4. A Newtonian fluid is one in which:
A. Density remains constant
B. Shear stress is proportional to velocity gradient
C. Pressure remains constant
D. Temperature remains constant
Answer: B. Shear stress is proportional to velocity gradient
Rationale: Newtonian fluids obey Newton’s law of viscosity, where shear stress
varies linearly with velocity gradient.
5. The specific gravity of a fluid is the ratio of its density to:
A. Air density
B. Absolute pressure
C. Density of water at standard conditions
D. Dynamic viscosity
Answer: C. Density of water at standard conditions
Rationale: Specific gravity compares a fluid’s density to the density of water.
6. Pressure in a stationary fluid increases with:
A. Decreasing depth
B. Increasing viscosity
,C. Increasing depth below the surface
D. Increasing velocity
Answer: C. Increasing depth below the surface
Rationale: Hydrostatic pressure increases because the weight of the fluid above
contributes to pressure at greater depths.
7. The pressure at a point in a static fluid acts:
A. Only upward
B. Only downward
C. Equally in all directions
D. Only horizontally
Answer: C. Equally in all directions
Rationale: Pascal’s law states that pressure at a point in a fluid at rest is
transmitted equally in all directions.
8. The hydrostatic pressure equation is:
A. P = ρV
B. P = ρgh
C. P = μV
D. P = Q/A
Answer: B. P = ρgh
Rationale: Hydrostatic pressure depends on fluid density, gravitational
acceleration, and depth.
9. The buoyant force on an immersed object equals:
A. Object weight
B. Fluid pressure
, C. Weight of displaced fluid
D. Fluid density only
Answer: C. Weight of displaced fluid
Rationale: Archimedes’ principle states that buoyant force equals the weight of
displaced fluid.
10. The continuity equation is based on conservation of:
A. Momentum
B. Energy
C. Mass
D. Entropy
Answer: C. Mass
Rationale: The continuity equation represents conservation of mass in a fluid
system.
11. For incompressible steady flow, the continuity equation becomes:
A. P₁ = P₂
B. A₁V₁ = A₂V₂
C. T₁ = T₂
D. F = ma
Answer: B. A₁V₁ = A₂V₂
Rationale: For incompressible flow, volume flow rate is conserved, so area and
velocity are inversely related.
12. The velocity of a fluid generally increases when flowing through a:
A. Larger area passage
B. Smaller area passage
