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Aero 315 Happy Studying Questions
with Detailed Verified Answers
Question: Why can streamlines be treated as material boundaries when they
form the walls of a stream tube? Can't air just flow across the streamline since
they are not really a material surface? (5.1)
Answer: Streamlines are defined as lines everywhere tangent to the local
velocity vector. So, even though a streamline is not material, air can't flow
across it
Question:
The continuity equation is a statement of which principle of physics? (5.2)
Answer: Conservation of mass
Question:
Which of the following assumptions is NOT necessary when using the
continuity equation? (5.5)
Answer: No nuclear reactions
Question:
When utilizing the Continuity Equation (Compressible form), what
assumptions must be made?
Answer: Steady, one-dimensional, area is perpendicular to the airflow
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Question:
A stream tube is defined as _________________? (5.1)
Answer: A collection of streamlines
Question:
On a hot summer day, you are standing inside a cabin looking at a manometer
that compares the outside air and inside air pressures. The outside
thermometer reads 95 deg F and the fluid in the manometer is water. The fluid
level in the manometer inside the cabin is 30 inches lower than it is outside the
cabin. If the pressure altitude in the cabin is 10,000 ft, what is the density of
the air outside? (4.4) Hint: Use Manometer Equation to find the pressure
outside, then the perfect gas law to find the density.
Answer: 0.0014 slugs/ft3
Question:
The standard atmosphere was built using these three relations:
Answer: Perfect gas, hydrostatic equation, and an empirical temperature
profile
Question:
According to Figure 2.4, at what altitude is the tropopause
Answer: 11km
Question:
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How does a standard altimeter work
Answer: It is a simple pressure gauge calibrated in units of altitude instead of
pressure
Question:
An aircraft's instruments measure an air temperature of 15 degC and an air
pressure of 83 kPa. What is the air density for these conditions? (Use Equation
2.1)
Answer: 1.0 kg/m^3
Question:
From Table B.1 in Appendix B, what is the atmospheric pressure on a standard
day at 10,000 ft altitude?
Answer: 1456 lb/ft^2
Question:
A manometer is filled with water. On the first side, the pressure is standard
sea level pressure (P1 = 101325 kPa). The second side is open to the room. The
fluid is 50cm higher on the second side than the first side. What is the pressure
in the room? Note: The density of water is 1000kg/m^3. Use Equation 2.3
Answer: 96425 Pa
Question:
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What would be considered by the USAF to be a valid reason for designing a
new aircraft?
Answer: National Security requires that we have the newest aircraft in the
world
Question:
What correctly describes one of the influences World War I had on aviation?
Answer: The large number of trained pilots and inexpensive surplus military
aircraft available in the US after the war led to a vast expansion of aviation
activities, enterprises, and public awareness
Question:
If you were designing a helicopter to land on the top of Mount Everest, and
you did some research to find out what the atmospheric conditions were
there, what step of the Engineering Method would you be accomplishing?
Answer: Collecting Info
Question:
What are the four fundamental flow properties that define the condition of a
fluid?
Answer: Temperature, Density, Velocity, and Pressure
Question:
When a gas is Perfect, or Ideal, what properties can be related in an equation?
Aero 315 Happy Studying Questions
with Detailed Verified Answers
Question: Why can streamlines be treated as material boundaries when they
form the walls of a stream tube? Can't air just flow across the streamline since
they are not really a material surface? (5.1)
Answer: Streamlines are defined as lines everywhere tangent to the local
velocity vector. So, even though a streamline is not material, air can't flow
across it
Question:
The continuity equation is a statement of which principle of physics? (5.2)
Answer: Conservation of mass
Question:
Which of the following assumptions is NOT necessary when using the
continuity equation? (5.5)
Answer: No nuclear reactions
Question:
When utilizing the Continuity Equation (Compressible form), what
assumptions must be made?
Answer: Steady, one-dimensional, area is perpendicular to the airflow
, Page | 2
Question:
A stream tube is defined as _________________? (5.1)
Answer: A collection of streamlines
Question:
On a hot summer day, you are standing inside a cabin looking at a manometer
that compares the outside air and inside air pressures. The outside
thermometer reads 95 deg F and the fluid in the manometer is water. The fluid
level in the manometer inside the cabin is 30 inches lower than it is outside the
cabin. If the pressure altitude in the cabin is 10,000 ft, what is the density of
the air outside? (4.4) Hint: Use Manometer Equation to find the pressure
outside, then the perfect gas law to find the density.
Answer: 0.0014 slugs/ft3
Question:
The standard atmosphere was built using these three relations:
Answer: Perfect gas, hydrostatic equation, and an empirical temperature
profile
Question:
According to Figure 2.4, at what altitude is the tropopause
Answer: 11km
Question:
, Page | 3
How does a standard altimeter work
Answer: It is a simple pressure gauge calibrated in units of altitude instead of
pressure
Question:
An aircraft's instruments measure an air temperature of 15 degC and an air
pressure of 83 kPa. What is the air density for these conditions? (Use Equation
2.1)
Answer: 1.0 kg/m^3
Question:
From Table B.1 in Appendix B, what is the atmospheric pressure on a standard
day at 10,000 ft altitude?
Answer: 1456 lb/ft^2
Question:
A manometer is filled with water. On the first side, the pressure is standard
sea level pressure (P1 = 101325 kPa). The second side is open to the room. The
fluid is 50cm higher on the second side than the first side. What is the pressure
in the room? Note: The density of water is 1000kg/m^3. Use Equation 2.3
Answer: 96425 Pa
Question:
, Page | 4
What would be considered by the USAF to be a valid reason for designing a
new aircraft?
Answer: National Security requires that we have the newest aircraft in the
world
Question:
What correctly describes one of the influences World War I had on aviation?
Answer: The large number of trained pilots and inexpensive surplus military
aircraft available in the US after the war led to a vast expansion of aviation
activities, enterprises, and public awareness
Question:
If you were designing a helicopter to land on the top of Mount Everest, and
you did some research to find out what the atmospheric conditions were
there, what step of the Engineering Method would you be accomplishing?
Answer: Collecting Info
Question:
What are the four fundamental flow properties that define the condition of a
fluid?
Answer: Temperature, Density, Velocity, and Pressure
Question:
When a gas is Perfect, or Ideal, what properties can be related in an equation?
