Day One Tech Flashcards
Scalar
a quantity that represents only magnitude, e.g., time, temperature, or volume
Vector
is a quantity that represents
magnitude and direction
Displacement
) is the distance and direction of a body’s movement
Velocity
) is the speed and direction of a body’s motion, the rate of
change of position
Speed
is a scalar equal to the
magnitude of the velocity vector
Acceleration
) is the rate and direction of a body’s change of velocity (gravity accelerates bodies toward the center of the earth at 32.174 ft/s2 )
Force
is a push or pull exerted on a body (1,000 lbs of thrust pushes a jet through the sky)
Mass
) is the quantity of molecular material that
comprises an object.
Volume
is the amount of space occupied by an object
Denisty
is mass per unit volume. It is expressed:
volume
mass
ρ = m/v
Weight
) is the force with which a mass is attracted toward the center of the earth by gravity.
Force
is mass times acceleration
Moment
is created when a force is applied at some distance from an axis or fulcrum,
and tends to produce rotation about that point. A moment is a vector quantity equal to a force
(F) times the distance (d) from the point of rotation that is perpendicular to the force (Figure
1-1-2). This perpendicular distance is called the moment arm.
Work
is done when a force acts on a body and moves
it. It is a scalar quantity equal to the force (F) times the
distance of displacement (s)
W = F * s
Power
is the rate of doing work or work done per unit
of time.
P = W/t
Energy
y is a scalar measure of a body’s capacity to do work. There are two types of energy:
potential energy and kinetic energy. Energy cannot be created or destroyed, but may be
transformed from one form to another. This principle is called conservation of energy. The
equation for total energy is:
TE = PE+KE
Potential Energy
is the ability of a body to do work because of its position or state of
being. It is a function of mass (m), gravity (g), and height (h):
PE = weight * height = mgh
Kinetic Energy
) is the ability of a body to do work because of its motion. It is a function of
mass (m) and velocity (V):
KE = 1/2mV^2
Work
may be performed on a body to change its position and give it potential energy or work
may give the body motion so that it has kinetic energy. Under ideal conditions, potential
energy may be completely converted to kinetic energy, and vice versa. The kinetic energy of a
glider in forward flight is converted into potential energy in a climb. As the glider’s velocity (KE)
diminishes, its altitude (PE) increases.
Newton’s First Law
The Law of Equilibrium:
“A body at rest tends to remain at rest and a body in motion tends to remain in
motion in a straight line at a constant velocity unless acted upon by some
unbalanced force.”
Equilibrium Flight
is the absence of acceleration, either linear or angular.
ar. Equilibrium flight exists when the
sum of all forces and the sum of all moments around the center of gravity are equal to zero.
An airplane in straight and level flight at a constant velocity is acted upon by four forces: thrust,
drag, lift and weight. When these forces exactly cancel each other out, the airplane is in
equilibrium
Trimmed Flight
exists when the sum of all moments around the center of gravity is equal to
zero. In trimmed flight, the sum of the forces may not be equal to zero. For example, an
airplane in a constant rate, constant angle of bank turn is in trimmed, but not equilibrium, flight.
An airplane in equilibrium flight, however, is always in trimmed flight
Newton’s Second Law
The law of accelration
An unbalanced force (F) acting on a body
produces an acceleration (a) in the direction of
the force that is directly proportional to the
force and inversely proportional to the mass
(m) of the body
a = F/m
Newton’s Third Law
The law of interaction
For every action, there is an equal and opposite reaction.
Hot gases exhausted rearward produce a thrust force acting forward
Atmospheric Makeup
Approximately 78% nitrogen, 21% oxygen, and 1% other gases, including argon and carbon dioxide. It is considered to be a uniform mixture
Static Pressure
is the pressure particles of air exert on adjacent bodies. Ambient static pressure is equal to the weight of a column of air over a given area. Decreases 1.0 inHg per 1000 ft
Air Density
the total mass of air particles per unit of volume. Air density decreases with an increase in altitude
Temperature
is a measure of the average random kinetic energy of air particles. Air temperature decreases linearly with an increase in altitude at a rate of 2 C per 1000’, until approximately 36,000’. This rate of temperature change is called the average lapse rate. From 36,000 to 66,000 feet, the air remains at a constant -56.5 and is called isothermal layer
Humidity
the amount of water vapor in the air. As humidity increases, water molecules displace an equal number of air molecules. Since water molecules have less mass and do not change the number of particles per unit of volume of air, density decreases. Humidity increases, air density decreases
Viscosity
The measure of the air’s resistance to flow and shearing. The tendency to stick to a surface. With air, as temperature increases, viscosity increases. The opposite with liquids
Local Speed of Sound
The rate at which sound waves travel through a particular air mass. The speed of sound, in air, is dependent only on the temperature of the air. As the temperature of air increases, the speed of sound increases.
Standard Atmosphere
29.92 /1013.25
59 / 15
3.57 per 1000 / 2 per 1000
local speed of sound = 661.7 knots
General Gas Law
The general gas law sets the relationship between three properties of air: pressure (P), density (p), and temperature (T). It is expressed as an equation where R is a constant for any given gas. P = pRT
Altitude is defined as the geometric height above a given plane of reference. True Altitude / Pressure Altitude
True : is the actual height above mean sea level
Pressure : the height above the standard datum plane. The datum plane is the actual elevation at which barometric pressure is 29.92. Since the standard datum plane is at sea level in the standard atmosphere, true altitude will be equal to pressure altitude.
Density Altitude
is the altitude in the standard atmosphere where the air density is equal
to local air density. It is found by correcting pressure altitude for temperature and humidity deviations from the standard atmosphere. In the standard atmosphere, density altitude is equal
to pressure altitude. But as temperature or humidity increase, the air becomes less dense,
with the effect that the actual air density at one altitude is equal to that of a higher altitude on a
standard day. A high DA indicates a low air density.
