Chapter 2 Oral questions Flashcards
Define matter
Any substance that occupies space and has mass
Name three states of matter
Solid, Liquid, gas
Define kinetic energy
the energy of motion
Work is the product of what two factors?
Force and distance moved (W = F X D)
What are the parts of a lever:
A rigid bar and a pivot point called the fulcrum
A wheelbarrow is what class of lever?
second class
(first class: see-saw, third class: tweezers)
Are all three states of matter affected by thermal expansion? If so, which is affected most?
All three are affected, gases are affected the most
What is a British Thermal Unit?
The amount of heat energy required to change the temperature of 1 pound of water 1 degree Fahrenheit
Three methods of heat transfer?
Conduction, convection, radiation
What term defines the temperature at which all molecular activity stops?
Absolute zero
Can liquids be compressed?
No, liquids are generally considered incompressible
What are the units used to express hydraulic or pneumatic pressure
Pounds per square inch (PSI)
Describe how pressure is transmitted when a force is applied to a confined liquid
Pressure is transmitted equally in all directions
What formula expresses the relationship between force, pressure, and area
Force = Area X Pressure (F over A I P)
What is the approximate speed of sound at sea level on a standard day?
661 knots or 340 meters per second
What is the atmospheric pressure at sea level on a standard day?
29.92 inches mercury or 1013.2 millibars
On a standard day at sea level, what is temperature?
59 degrees Fahrenheit, 15 Celsius
What are the factors that determine density altitude?
Temperature and atmospheric pressure
What is the term used to describe the ratio between the amount of moisture actually present in the atmosphere compared to the amount the air could hold?
Relative Humidity
What are the four principle forces acting on an airplane in flight?
Lift, Gravity, Thrust, Drag
What is the term that describes the angle between the relative wind and the chord line of an airfoil?
Angle of Attack
What are the factors that cause a wing to stall?
when the angle of attack exceeds a critical value and the airflow separates from the upper surface and becomes turbulent
What are the principle effects that result from lowering the flaps while in flight?
Lift increases, drag increases, and stall speed decreases
What is the function of a wing mounted vortex generator?
They delay or prevent airflow from separating from the upper surface of a wing during high speed flight (prevent boundary layer separation)
How does blade flapping help to compensate for dis-symmetry of lift in helicopter main rotor systems?
Flapping increases the angle of attack and lift on the retreating blade and decreases AOA and lift on advancing blade
How does the airflow through the main rotor of a helicopter change during the transition from normal flight to auto-rotation?
During normal flight air moves downward, in auto-rotation air moves upward
What is friction?
opposition to relative motion between two objects in contact with each other
