Dale Crane's Oral and Practical Exam Guide:
General; Basic Physics Questions And Answers
Verified 100% Correct
What is an example of heat transfer by radiation? - ANSWER- -The heating of the
Earth's surface by heat transmitted through space from the sun
-Conduction and convection cannot wholly account for some of the phenomena
associated with heat transfer. For example, the heat one feels when sitting in front of an
open re cannot be transferred by convection because the air currents are moving
toward the re. It cannot be transferred through conduction because the conductivity of
the air is very small, and the cooler currents of air moving toward the re would more
than overcome the transfer of heat outward. Therefore, there must be some way for
heat to travel across space other than by conduction and convection. The existence of
another process of heat transfer is still more evident when the heat from the sun is
considered. Since conduction and convection take place only through some medium,
such as a gas or a liquid, heat from the sun must reach the earth by another method,
since space is an almost perfect vacuum. Radiation is the name given to this third
method of heat transfer. The term "radiation" refers to the continual emission of energy
from the surface of all bodies. This energy is known as radiant energy. It is in the form
of elec- tromagnetic waves, radio waves, or x-rays, which are all alike except for a
difference in wave length. These waves travel at the velocity of light and are transmitted
through a vacuum more easily than through air because air absorbs some of them.
Most forms of energy can be traced back to the energy of sunlight. Sunlight is a form of
radiant heat energy that travels through space to reach the earth. These
electromagnetic heat waves are absorbed when they come in contact with non-
transparent bodies. The result is that the motion of the molecules in the body is
increased as indicated by an increase in the temperature of the body. (FAA-H-8083-30,
Ch. 03)
Why do most metals expand when they are heated? - ANSWER- As heat heat is
absorbed, the electrons move faster and expand their orbits in the molecules of the
metal
What is meant by the density of air? - ANSWER- The weight of a given volume of air
What is meant by relative wind with regard to an airfoil? - ANSWER- -The direction the
wind strikes an airfoil
-Whatever direction the airplane is ying, the relative wind is in the opposite direction. If
the airplane is ying due north, and someone in the airplane is not shielded from the
, elements, that person will feel like the wind is coming directly from the south. (FAA-
H8083-30, Ch. 03)
What is meant by the angle of attack? - ANSWER- -The acute angle formed between
the chord line of an airfoil and the direction the air strikes the airfoil
-The angle between the chord line and the relative wind is the angle of attack. As the
angle of attack increases, the lift on the wing increases. If the angle of attack becomes
too great, the air ow can separate from the wing and the lift will be destroyed. When this
occurs, a condition known as a stall takes place. (FAA-H-8083-30, Ch. 03)
What is meant by the critical angle of attack? - ANSWER- The highest angle of attack at
which the air passes over the airfoil in a smooth flow. Above the critical angle of attack
the airflow breaks away and becomes turbulent
What is meant by the stagnation point of an airfoil? - ANSWER- The point on the
leading edge of an airfoil at which the airflow separates, some flowing over the top and
some over the bottom
What is the difference between speed and velocity? - ANSWER- -Speed is the rate at
which an object is moving. Velocity is the vector quantity that expresses both the rate
and direction an object is moving
-In everyday conversation, speed and velocity are often used as if they mean the same
thing. In physics they have definite and distinct meanings. Speed refers to how fast an
object is moving, or how far the object will travel in a specific time. The speed of an
object tells nothing about the direction an object is moving. For example, if the
information is supplied that an airplane leaves New York City and travels 8 hours at a
speed of 150 mph, this information tells nothing about the direction in which the airplane
is moving. At the end of 8 hours, it might be in Kansas City, or if it traveled in a circular
route, it could be back in New York City. Velocity is that quantity in physics which
denotes both the speed of an object and the direction in which the object moves.
Velocity can be defined as the rate of motion in a particular direction. Velocity is also
described as being a vector quantity, a vector being a line of specific length, having an
arrow on one end or the other. The length of the line indicates the number value and the
arrow indicates the direction in which that number is acting. (FAA-H-8083-30, Ch. 03)
What is meant by air density? - ANSWER- The mass of air in a given volume
What is meant by weight? - ANSWER- The measure of the force gravity acting on a
body
What is meant by thrust? - ANSWER- -The forward aerodynamic force produced by a
propeller, fan, or turbojet engine as it forces air to the rear, behind the airplane -When
an aircraft propeller pushes a stream of air back- ward with a force of 500 lb, the air
pushes the blades forward with a force of 500 lb. This forward force causes the aircraft
General; Basic Physics Questions And Answers
Verified 100% Correct
What is an example of heat transfer by radiation? - ANSWER- -The heating of the
Earth's surface by heat transmitted through space from the sun
-Conduction and convection cannot wholly account for some of the phenomena
associated with heat transfer. For example, the heat one feels when sitting in front of an
open re cannot be transferred by convection because the air currents are moving
toward the re. It cannot be transferred through conduction because the conductivity of
the air is very small, and the cooler currents of air moving toward the re would more
than overcome the transfer of heat outward. Therefore, there must be some way for
heat to travel across space other than by conduction and convection. The existence of
another process of heat transfer is still more evident when the heat from the sun is
considered. Since conduction and convection take place only through some medium,
such as a gas or a liquid, heat from the sun must reach the earth by another method,
since space is an almost perfect vacuum. Radiation is the name given to this third
method of heat transfer. The term "radiation" refers to the continual emission of energy
from the surface of all bodies. This energy is known as radiant energy. It is in the form
of elec- tromagnetic waves, radio waves, or x-rays, which are all alike except for a
difference in wave length. These waves travel at the velocity of light and are transmitted
through a vacuum more easily than through air because air absorbs some of them.
Most forms of energy can be traced back to the energy of sunlight. Sunlight is a form of
radiant heat energy that travels through space to reach the earth. These
electromagnetic heat waves are absorbed when they come in contact with non-
transparent bodies. The result is that the motion of the molecules in the body is
increased as indicated by an increase in the temperature of the body. (FAA-H-8083-30,
Ch. 03)
Why do most metals expand when they are heated? - ANSWER- As heat heat is
absorbed, the electrons move faster and expand their orbits in the molecules of the
metal
What is meant by the density of air? - ANSWER- The weight of a given volume of air
What is meant by relative wind with regard to an airfoil? - ANSWER- -The direction the
wind strikes an airfoil
-Whatever direction the airplane is ying, the relative wind is in the opposite direction. If
the airplane is ying due north, and someone in the airplane is not shielded from the
, elements, that person will feel like the wind is coming directly from the south. (FAA-
H8083-30, Ch. 03)
What is meant by the angle of attack? - ANSWER- -The acute angle formed between
the chord line of an airfoil and the direction the air strikes the airfoil
-The angle between the chord line and the relative wind is the angle of attack. As the
angle of attack increases, the lift on the wing increases. If the angle of attack becomes
too great, the air ow can separate from the wing and the lift will be destroyed. When this
occurs, a condition known as a stall takes place. (FAA-H-8083-30, Ch. 03)
What is meant by the critical angle of attack? - ANSWER- The highest angle of attack at
which the air passes over the airfoil in a smooth flow. Above the critical angle of attack
the airflow breaks away and becomes turbulent
What is meant by the stagnation point of an airfoil? - ANSWER- The point on the
leading edge of an airfoil at which the airflow separates, some flowing over the top and
some over the bottom
What is the difference between speed and velocity? - ANSWER- -Speed is the rate at
which an object is moving. Velocity is the vector quantity that expresses both the rate
and direction an object is moving
-In everyday conversation, speed and velocity are often used as if they mean the same
thing. In physics they have definite and distinct meanings. Speed refers to how fast an
object is moving, or how far the object will travel in a specific time. The speed of an
object tells nothing about the direction an object is moving. For example, if the
information is supplied that an airplane leaves New York City and travels 8 hours at a
speed of 150 mph, this information tells nothing about the direction in which the airplane
is moving. At the end of 8 hours, it might be in Kansas City, or if it traveled in a circular
route, it could be back in New York City. Velocity is that quantity in physics which
denotes both the speed of an object and the direction in which the object moves.
Velocity can be defined as the rate of motion in a particular direction. Velocity is also
described as being a vector quantity, a vector being a line of specific length, having an
arrow on one end or the other. The length of the line indicates the number value and the
arrow indicates the direction in which that number is acting. (FAA-H-8083-30, Ch. 03)
What is meant by air density? - ANSWER- The mass of air in a given volume
What is meant by weight? - ANSWER- The measure of the force gravity acting on a
body
What is meant by thrust? - ANSWER- -The forward aerodynamic force produced by a
propeller, fan, or turbojet engine as it forces air to the rear, behind the airplane -When
an aircraft propeller pushes a stream of air back- ward with a force of 500 lb, the air
pushes the blades forward with a force of 500 lb. This forward force causes the aircraft
