Important Notes:
•Mass is the quantity of molecular material that comprise an object.
•Weight is the force at which a mass is attracted toward the center of the earth by gravity.
•The density of the air is the mass of air per unit of volume.
•A force is a push or pull exerted on a body. It tends to produce motion along a line. A moment is a tendency to produce motion about a point or axis. It is created by applying force to a lever arm to induce rotational motion about an axis.
•Work is done when a force acts on a body and moves it.
•Power is the rate of doing work
•Energy is the ability to work
•Potential energy is the ability of a body to do work because of its position or state of being.
•Kinetic energy is the ability of a body to do work because of it’s motion.
•Newton’s Firs Law of Motion is 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.
•An airplane traveling at a constant speed and direction, and an airplane parked on the flight line are in equilibrium if the sum of the forces and moments about the center of gravity equal zero.
•Trimmed flight exists when the sum of the moments acting about the C.G. equals zero where equilibrium flight exists when the sum of the forces and moments about the C.G. equal zero.
•Newton’s Second Law of Motion is the Law of Acceleration: “An unbalanced force acting on a body produces an acceleration in the direction of the force that is directly proportional to the force and inversely proportional to the mass of the body. An example would be an aircraft in a turn.
•Static pressure is the weight of a column of air over a given area. Static pressure decreases with an increase in altitude.
•Air density decreases with an increase in altitude.
•Air temperature is a measure of the average kinetic energy of air particles
•Air temperature decreases by 2.0 C per 1,000 ft until 36,000 feet.
•Air density decreases with an increase in humidity
•Air viscosity is a measure of air’s resistance to flow and shearing. Air viscosity increases with an increase in temperature.
•The primary factor in determining the speed of sound is air temperature.
•Given a constant pressure, density will decrease with an increase in temperature.