MAE 201 Final Exam – Aerospace Engineering
Fundamentals Actual Exam | 100% Pass | Correct
Answers & Detailed Rationales Pass Guaranteed
- A+ Graded
Standard Atmosphere & Aerodynamics Fundamentals
Q1: In the International Standard Atmosphere (ISA) model, what is the standard
temperature lapse rate in the troposphere?
A. -9.8°C/km
B. -6.5°C/km
C. -5.4°C/km
D. -2.0°C/km
Correct Answer: B
Rationale: This choice is correct because the ISA defines the temperature lapse rate in
the troposphere (from sea level up to 11 km) as a linear decrease of 6.5 degrees
Celsius per kilometer.
Q2: An aircraft is flying at an altitude where the temperature is significantly higher than
the ISA standard for that altitude. How does this affect the density altitude compared to
the pressure altitude?
A. Density altitude is lower than pressure altitude.
B. Density altitude is equal to pressure altitude.
C. Density altitude is higher than pressure altitude.
D. Density altitude is only affected by pressure, not temperature.
Correct Answer: C
Rationale: This choice is correct because warmer air is less dense; if the temperature is
higher than standard, the air density decreases, causing the density altitude (the altitude
the aircraft "thinks" it is at) to be higher than the pressure altitude.
Q3: Which of the following statements correctly describes the relationship between
Calibrated Airspeed (CAS), Equivalent Airspeed (EAS), and True Airspeed (TAS) in
subsonic flight?
A. TAS > EAS > CAS
B. CAS > EAS > TAS
C. TAS > CAS > EAS
, D. CAS > TAS > EAS
Correct Answer: C
Rationale: This choice is correct because True Airspeed increases with altitude due to
lower density, while Equivalent Airspeed is CAS corrected for position error and
compressibility; thus, TAS is typically the highest value in cruise, followed by CAS, then
EAS.
Q4: What is the defining characteristic of the stratosphere in the standard atmosphere?
A. Temperature decreases linearly with altitude.
B. Temperature remains constant (isothermal) up to approximately 20 km.
C. Pressure increases with altitude.
D. The air is completely still and contains no moisture.
Correct Answer: B
Rationale: This choice is correct because in the standard atmosphere model, the
stratosphere begins at the tropopause (11 km) and features a constant temperature of
-56.5°C (isothermal layer) up to about 20 km before temperature rises again.
Q5: The Reynolds number (Re) is a dimensionless quantity used to predict flow
patterns. What is the physical significance of Re?
A. The ratio of inertial forces to viscous forces.
B. The ratio of pressure forces to gravitational forces.
C. The ratio of speed of sound to flow velocity.
D. The ratio of lift to drag.
Correct Answer: A
Rationale: This choice is correct because Reynolds number quantifies the relative
importance of fluid inertia versus fluid viscosity; high Re indicates turbulent inertial flow
dominates, while low Re indicates viscous effects are significant.
Q6: As altitude increases in the standard atmosphere, how does the kinematic viscosity
of the air change?
A. It decreases because the air gets colder.
B. It remains constant because viscosity is a fluid property.
C. It increases because density drops faster than dynamic viscosity.
D. It decreases because the pressure drops.
Correct Answer: C
Rationale: This choice is correct while dynamic viscosity changes slightly with
temperature, the density drops off rapidly with altitude, causing the kinematic viscosity
(dynamic viscosity divided by density) to increase significantly.
Q7: An aircraft is flying at a Mach number of 0.75 at sea level where the speed of sound
is roughly 661 knots. What is the aircraft's True Airspeed?
Fundamentals Actual Exam | 100% Pass | Correct
Answers & Detailed Rationales Pass Guaranteed
- A+ Graded
Standard Atmosphere & Aerodynamics Fundamentals
Q1: In the International Standard Atmosphere (ISA) model, what is the standard
temperature lapse rate in the troposphere?
A. -9.8°C/km
B. -6.5°C/km
C. -5.4°C/km
D. -2.0°C/km
Correct Answer: B
Rationale: This choice is correct because the ISA defines the temperature lapse rate in
the troposphere (from sea level up to 11 km) as a linear decrease of 6.5 degrees
Celsius per kilometer.
Q2: An aircraft is flying at an altitude where the temperature is significantly higher than
the ISA standard for that altitude. How does this affect the density altitude compared to
the pressure altitude?
A. Density altitude is lower than pressure altitude.
B. Density altitude is equal to pressure altitude.
C. Density altitude is higher than pressure altitude.
D. Density altitude is only affected by pressure, not temperature.
Correct Answer: C
Rationale: This choice is correct because warmer air is less dense; if the temperature is
higher than standard, the air density decreases, causing the density altitude (the altitude
the aircraft "thinks" it is at) to be higher than the pressure altitude.
Q3: Which of the following statements correctly describes the relationship between
Calibrated Airspeed (CAS), Equivalent Airspeed (EAS), and True Airspeed (TAS) in
subsonic flight?
A. TAS > EAS > CAS
B. CAS > EAS > TAS
C. TAS > CAS > EAS
, D. CAS > TAS > EAS
Correct Answer: C
Rationale: This choice is correct because True Airspeed increases with altitude due to
lower density, while Equivalent Airspeed is CAS corrected for position error and
compressibility; thus, TAS is typically the highest value in cruise, followed by CAS, then
EAS.
Q4: What is the defining characteristic of the stratosphere in the standard atmosphere?
A. Temperature decreases linearly with altitude.
B. Temperature remains constant (isothermal) up to approximately 20 km.
C. Pressure increases with altitude.
D. The air is completely still and contains no moisture.
Correct Answer: B
Rationale: This choice is correct because in the standard atmosphere model, the
stratosphere begins at the tropopause (11 km) and features a constant temperature of
-56.5°C (isothermal layer) up to about 20 km before temperature rises again.
Q5: The Reynolds number (Re) is a dimensionless quantity used to predict flow
patterns. What is the physical significance of Re?
A. The ratio of inertial forces to viscous forces.
B. The ratio of pressure forces to gravitational forces.
C. The ratio of speed of sound to flow velocity.
D. The ratio of lift to drag.
Correct Answer: A
Rationale: This choice is correct because Reynolds number quantifies the relative
importance of fluid inertia versus fluid viscosity; high Re indicates turbulent inertial flow
dominates, while low Re indicates viscous effects are significant.
Q6: As altitude increases in the standard atmosphere, how does the kinematic viscosity
of the air change?
A. It decreases because the air gets colder.
B. It remains constant because viscosity is a fluid property.
C. It increases because density drops faster than dynamic viscosity.
D. It decreases because the pressure drops.
Correct Answer: C
Rationale: This choice is correct while dynamic viscosity changes slightly with
temperature, the density drops off rapidly with altitude, causing the kinematic viscosity
(dynamic viscosity divided by density) to increase significantly.
Q7: An aircraft is flying at a Mach number of 0.75 at sea level where the speed of sound
is roughly 661 knots. What is the aircraft's True Airspeed?
