Flashcards in Physics Deck (82)
What is meant by a temperature of absolute zero?
The temperature at which all molecular movement stops.
What is the standard day barometric altimeter setting?
Define kinetic energy.
Energy due to motion, defined as one half mass times velocity squared.
What is a BTU (British Thermal Unit)?
A unit of heat, one BTU equals the heat energy required to raise one pound of water one degree fahrenheit.
What are three methods of heat transfer?
Conduction, convection and radiation.
The force that resists the relative motion of two bodies in contact.
What are the two factors involved in work?
Force and distance.
Name the parts of a basic lever.
The bar and the fulcrum.
What class of lever is the wheelbarrow?
What is the standard day temperature?
59 degrees Fahrenheit.
What factors are considered in determining density altitude?
Pressure and temperature.
Define relative humidity.
Ratio of the existing amount of water vapor in the air at a given temperature to the maximum amount that could exist at that temperature; usually expressed in percent.
What is the nature of pressure in confined fluids?
Pressure acts equally in all directions.
What unit is used to describe pressure in hydraulic systems?
(pounds per square inch)
What is the basic formula for computing force?
Force = Pressure x Area
Are liquids compressible?
Liquids are considered incompressible.
What are the three basic physical states in which matter can exist?
Solid, liquid and gas.
What is meant by matter?
Anything that occupies space and has weight.
What is the approximate speed of sound on a standard day at seal level?
What types of matter are affected by thermal expansion?
Solids, liquids, and gases.
Name the four forces of flight.
Lift, thrust, weight, and drag.
What is the angle between the chord line of an airfoil and the relative wind striking it?
Angle of Attack (AOA).
What causes an airfoil to stall?
The separation of airflow across the top of the wing from the wings upper surface.
What is the function of a vortex generator?
The generated vortices aid in preventing airflow separation, this reduces stall speed and can increase takeoff and landing performance.
What is the purpose of flaps?
To increase lift, decrease stall speed, and create drag.
What is the difference of air flow in helicopter powered flight and in autorotation?
Air flow is reversed. In powered flight air is drawn downward by the main rotor system, during autorotation airflow enters the rotor system from below as the helicopter descends.
What does blade flapping do for helicopters?
Minimizes asymmetrical lift by increasing the AOA of the retreating blade while decreasing the AOA of the advancing blade.
What is meant by pressure?
Force that acts on a unit of area.
What is the standard sea level atmospheric pressure expressed in inches of mercury, and in pounds per square inches?
29.92 inches of mercury and 14.69 pounds per square inch.