SOLUTIONS MANUAL –
FUNDAMENTALS OF FLUID
MECHANICS 9TH EDITION |
MUNSON, YOUNG, OKIISHI
| PDF
Fundamentals of Fluid Mechanics (9th Edition) –
Munson, Young, Okiishi
Comprehensive Practice Exam | Questions with Bolded
Correct Answers & Detailed Rationales
Based on the official 12-chapter structure
Chapter 1: Introduction (Questions 1–25)
1. A fluid is defined as a substance that:
A. Has a fixed shape
B. Deforms continuously when acted on by a shearing stress of any magnitude
,C. Cannot flow
D. Has infinite viscosity
Rationale: From Section 1.1 of the text: "A fluid is defined as a substance that deforms
continuously when acted on by a shearing stress of any magnitude" .
2. A Bingham plastic does NOT satisfy the definition of a fluid because:
A. It has zero viscosity
B. It exhibits a strain rate of zero if the applied shear stress is lower than its yield
stress
C. It is incompressible
D. It has infinite viscosity
Rationale: A Bingham plastic behaves like a Newtonian fluid for shear stress larger than
its yield stress, but exhibits zero strain rate (like a solid) if the applied shear stress is
lower than the yield stress. Because it has a finite yield stress, its behavior does not
satisfy the definition of a fluid .
3. Drilling mud is frequently modeled as a Bingham plastic because:
A. It has zero viscosity
B. It has a finite yield stress
C. It is a perfect gas
D. It has no surface tension
Rationale: Drilling mud is used to carry debris to the surface and cool/lubricate the drill
bit. It is frequently modeled as a Bingham plastic due to its finite yield stress .
4. The force of wind blowing against a building is given by F = C_D ρ V² A / 2. The
drag coefficient C_D is:
A. Dimensionful
B. Dimensionless
C. Measured in Newtons
D. Measured in kg/m³
Rationale: Using dimensional analysis: F ~ MLT⁻², ρ ~ ML⁻³, V ~ LT⁻¹, A ~ L². C_D =
2F/(ρV²A) has dimensions M⁰L⁰T⁰. Hence, C_D is dimensionless .
5. The Mach number is defined as:
,A. The ratio of fluid velocity to the speed of sound
B. The ratio of the velocity of an object in a fluid to the speed of sound in the fluid
C. The ratio of density to viscosity
D. The ratio of pressure to temperature
Rationale: The Mach number is a dimensionless ratio of the velocity of an object in a
fluid to the speed of sound in the fluid: Ma = V/√(kRT) .
6. Which of the following is a primary dimension in the MLT system?
A. Force
B. Energy
C. Mass
D. Pressure
Rationale: The MLT system uses Mass (M), Length (L), and Time (T) as primary
dimensions. Force, energy, and pressure are derived dimensions (Original).
7. The specific weight of a fluid is defined as:
A. Mass per unit volume
B. Weight per unit volume
C. Density times velocity
D. Viscosity times density
Rationale: Specific weight γ = ρg, where ρ is density and g is gravitational acceleration
(Original).
8. A fluid with a specific gravity of 0.85 has a density of:
A. 850 kg/m³
B. 850 kg/m³
C. 85 kg/m³
D. 8,500 kg/m³
Rationale: SG = ρ_fluid / ρ_water. ρ_water = 1000 kg/m³, so ρ_fluid = 0.85 × 1000 =
850 kg/m³ .
9. A fluid has viscosity 0.005 Pa·s and specific gravity 0.85. Its kinematic viscosity
in m²/s is:
A. 5.88 × 10⁻⁶
B. 5.88 × 10⁻⁶
, C. 4.25 × 10⁻³
D. 5.88 × 10⁻³
Rationale: ν = μ/ρ = 0. = 5.88 × 10⁻⁶ m²/s .
10. The ideal gas law is expressed as:
A. pV = nRT
B. p = ρRT
C. pV = mRT
D. p = ρRT
Rationale: The ideal gas law in fluid mechanics is typically written as p = ρRT, where R is
the gas constant for the specific gas (Original).
11. Viscosity is a measure of a fluid's:
A. Compressibility
B. Resistance to deformation under shear stress
C. Surface tension
D. Vapor pressure
Rationale: Viscosity is the property of a fluid that quantifies its resistance to gradual
deformation by shear stress (Original).
12. A Newtonian fluid is one where:
A. Shear stress is independent of strain rate
B. Shear stress is linearly proportional to strain rate
C. Shear stress is proportional to strain rate squared
D. Strain rate is zero for any stress
Rationale: For a Newtonian fluid, τ = μ(du/dy), where shear stress is linearly
proportional to the velocity gradient (Original).
13. The no-slip condition states that:
A. Fluid velocity at a solid boundary is zero
B. Fluid velocity at a solid boundary equals the velocity of the boundary
C. Fluid velocity at a solid boundary is infinite
D. Fluid velocity at a solid boundary is independent of the boundary
FUNDAMENTALS OF FLUID
MECHANICS 9TH EDITION |
MUNSON, YOUNG, OKIISHI
Fundamentals of Fluid Mechanics (9th Edition) –
Munson, Young, Okiishi
Comprehensive Practice Exam | Questions with Bolded
Correct Answers & Detailed Rationales
Based on the official 12-chapter structure
Chapter 1: Introduction (Questions 1–25)
1. A fluid is defined as a substance that:
A. Has a fixed shape
B. Deforms continuously when acted on by a shearing stress of any magnitude
,C. Cannot flow
D. Has infinite viscosity
Rationale: From Section 1.1 of the text: "A fluid is defined as a substance that deforms
continuously when acted on by a shearing stress of any magnitude" .
2. A Bingham plastic does NOT satisfy the definition of a fluid because:
A. It has zero viscosity
B. It exhibits a strain rate of zero if the applied shear stress is lower than its yield
stress
C. It is incompressible
D. It has infinite viscosity
Rationale: A Bingham plastic behaves like a Newtonian fluid for shear stress larger than
its yield stress, but exhibits zero strain rate (like a solid) if the applied shear stress is
lower than the yield stress. Because it has a finite yield stress, its behavior does not
satisfy the definition of a fluid .
3. Drilling mud is frequently modeled as a Bingham plastic because:
A. It has zero viscosity
B. It has a finite yield stress
C. It is a perfect gas
D. It has no surface tension
Rationale: Drilling mud is used to carry debris to the surface and cool/lubricate the drill
bit. It is frequently modeled as a Bingham plastic due to its finite yield stress .
4. The force of wind blowing against a building is given by F = C_D ρ V² A / 2. The
drag coefficient C_D is:
A. Dimensionful
B. Dimensionless
C. Measured in Newtons
D. Measured in kg/m³
Rationale: Using dimensional analysis: F ~ MLT⁻², ρ ~ ML⁻³, V ~ LT⁻¹, A ~ L². C_D =
2F/(ρV²A) has dimensions M⁰L⁰T⁰. Hence, C_D is dimensionless .
5. The Mach number is defined as:
,A. The ratio of fluid velocity to the speed of sound
B. The ratio of the velocity of an object in a fluid to the speed of sound in the fluid
C. The ratio of density to viscosity
D. The ratio of pressure to temperature
Rationale: The Mach number is a dimensionless ratio of the velocity of an object in a
fluid to the speed of sound in the fluid: Ma = V/√(kRT) .
6. Which of the following is a primary dimension in the MLT system?
A. Force
B. Energy
C. Mass
D. Pressure
Rationale: The MLT system uses Mass (M), Length (L), and Time (T) as primary
dimensions. Force, energy, and pressure are derived dimensions (Original).
7. The specific weight of a fluid is defined as:
A. Mass per unit volume
B. Weight per unit volume
C. Density times velocity
D. Viscosity times density
Rationale: Specific weight γ = ρg, where ρ is density and g is gravitational acceleration
(Original).
8. A fluid with a specific gravity of 0.85 has a density of:
A. 850 kg/m³
B. 850 kg/m³
C. 85 kg/m³
D. 8,500 kg/m³
Rationale: SG = ρ_fluid / ρ_water. ρ_water = 1000 kg/m³, so ρ_fluid = 0.85 × 1000 =
850 kg/m³ .
9. A fluid has viscosity 0.005 Pa·s and specific gravity 0.85. Its kinematic viscosity
in m²/s is:
A. 5.88 × 10⁻⁶
B. 5.88 × 10⁻⁶
, C. 4.25 × 10⁻³
D. 5.88 × 10⁻³
Rationale: ν = μ/ρ = 0. = 5.88 × 10⁻⁶ m²/s .
10. The ideal gas law is expressed as:
A. pV = nRT
B. p = ρRT
C. pV = mRT
D. p = ρRT
Rationale: The ideal gas law in fluid mechanics is typically written as p = ρRT, where R is
the gas constant for the specific gas (Original).
11. Viscosity is a measure of a fluid's:
A. Compressibility
B. Resistance to deformation under shear stress
C. Surface tension
D. Vapor pressure
Rationale: Viscosity is the property of a fluid that quantifies its resistance to gradual
deformation by shear stress (Original).
12. A Newtonian fluid is one where:
A. Shear stress is independent of strain rate
B. Shear stress is linearly proportional to strain rate
C. Shear stress is proportional to strain rate squared
D. Strain rate is zero for any stress
Rationale: For a Newtonian fluid, τ = μ(du/dy), where shear stress is linearly
proportional to the velocity gradient (Original).
13. The no-slip condition states that:
A. Fluid velocity at a solid boundary is zero
B. Fluid velocity at a solid boundary equals the velocity of the boundary
C. Fluid velocity at a solid boundary is infinite
D. Fluid velocity at a solid boundary is independent of the boundary
