Flashcards in General Chapter 02 Deck (27)
Any substance that occupies space and has mass.
Matter may exist in what three states?
Solid, liquid and gas.
Define kinetic energy.
Kinetic energy is the energy of motion.
Work is the product of what two factors?
Force and the distance moved.
What are the parts of a lever?
A rigid bar and a pivot point called the fulcrum.
A wheelbarrow is an example of what class of lever?
A second-class lever.
Are all three states of matter affected by thermal expansion and if so, which state is affected most?
All three states are affected, with gases being 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.
Name the three methods of heat transfer?
Conduction, convection and radiation.
What term defines the temperature at which all molecular motion ceases?
Can liquids be compressed?
No, liquids are generally considered in-compressible.
What are the customary units used to express hydraulic or pneumatic pressure in the United States?
Pounds per square inch.
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 equals area times pressure.
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 of Mercury or 1013.2 millibars.
On a standard day at sea level, what is the value for temperature?
59°F or 15°C.
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 as compared to the amount the air could hold if lt were completely saturated?
What are the four principle forces acting on an airplane in flight?
Lift, drag, thrust and gravity.
What is the term that describes the angle between the relative wind and the chord line of an airfoil?
The Angle of Attack.
What are the factors that cause an airplane wing to stall?
Stall is caused 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?
Vortex generators delay or keep the airflow from separating from the upper surface of a wing during high speed flight.
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 the angle of attack and lift on the 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 the air moves downward and during auto-rotation the air moves upward.