POF KAP 1 Flashcards
When an aircraft is moving, there are four main forces acting upon it, which?
Weight
Lift
Thrust
Drag
Unit for Mass
Kilogram (kg)
Mass definition
The quantity of matter in a body
Unit for Force
Newton (N)
Unit of Weight
Newton (N) - the force due to gravity
F =
mass * acceleration due to gravity (m*g)
What is the value of acceleration due to gravity ?
9,81 newtons or 9,81 m/s^2
Definition of centre of gravity
The point which the weight of an aircraft acts.
Unit Work
Joule (J)
Definition Work
A force is said to do work on a body, when it moves the body in the direction in which the force is acting.
Work =
Force * Distance (through which the force is applied)
Find F
The mass of a B737 is 60000 kg
F = mg
F= 600009,81
F= 588600 N
Find Work
A force of 10N moves a body 2m along its line of action.
Work = Force * Distance
Work = 10N *2m
Work = 20 Nm or J
Nm is the same as?
Joule (J)
Unit for Power
Watt (W)
Definition Power
The time taken to do work
Power =
Force (N) * Distance (m) / Time (s)
Joules per second is the same as?
Watt (W)
Find Power
If a force of 10N moves a mass 2m in 5 seconds
Power = Force (N) * Distance (m) / Time (s)
Power = (10*2)/5
Power = 4 joules per second or Watt
Density is??
The “thickness” of air
A given mass flow will generate the required lift force, but a decrease in air density will reduce the mass flow.
How is the mass flow maintained?
To maintain the mass flow, the speed of the aircraft through the air must be increased.
Definition of Density
Mass per unit volume (kg/m^3)
The number of air particles in a given space
ISA
International standard atmosphere (ICAO)
15 degrees
1013,25 hPa
1,225 kg/m^3
Unit for Energi
Joule (J)
Kinetic energy formula
KE = 1/2m *V^2
Hence more speed = more kinetic energy
Newtons first law
A body will remain at rest or in uniform motion in a straight line unless acted on by an external force
‘To move a stationary object or to make a moving object change its direction, a force must be applied’
Newtons second law
The acceleration of a body from state of rest, or uniform motion in a straight line, is proportional to the applied force and inversely proportional to the mass.
Unit for Velocity
m/s
Definition for Velocity
Rate of change of displacement
Unit Acceleration
m/s^2
Rate of chance of velocity
Acceleration formula
Acceleration = Force/Mass
Unit Momentum
kg-m/s (mass*velocity)
The quantity of motion possessed by a body
Newtons third law
Every action has an equal opposite reaction.
Definition Aerofoil
A body with a surface that provides the most favourable ratio between lift and drag in flight.
Definition Attitude
The nose up/down orientation of an aircraft relative to the horizon.
Definition Angle of attack (AOA)
The angle between the chord line and the relative wind
Definition Load factor
The ratio of the weight of an aircraft to the load imposed by lift.
Load factor = Lift/Weight
Mach number
The ratio of the True airspeed to the speed of sound in the surrounding medium.
What is Oscillation?
A vibration
Definition Relative airflow
The direction of airflow produced by the aircraft moving through the air.
True airspeed (TAS or V)
The speed at which the aircraft is travelling through the air.
Definition Velocity
Speed with direction
Definition Wake
The region of air behind an aircraft in which the total pressure has been changed by the presence of the aircraft.
Definition Wing loading
Ratio of aircraft weight to wing area
Wing loading = Aircraft/Wing area
An aircrafts mass is a result of?
How much matter it contains
The unit of mass is ….
kg
The definition of a force is…
A push or pull
The unit of force is …
Newton
About which point does an aircraft rotate?
The centre of gravity
If a force is applied to a mass and the mass does not move…
No work is done
The unit of work is …
Joule
The unit of power is …
Watt
Kinetic energy is ?
The energy a mass possesses because of its motion.
The definition of velocity is ?
The rate of change of displacement
The definition of momentum is ?
The quantity of motion possessed by a body
