Physics and Aircraft Fundamentals

Flashcards covering fundamental physics concepts, flight mechanics, forces, fluid dynamics, and thermodynamics based on lecture notes.

Trivalent Atom

An atom containing 3 valence electrons in its outer shell.

Primary Subatomic Particles

Protons (positive charges in nucleus), Neutrons (neutral in nucleus), and Electrons (negatively charged orbiting nucleus and outer shells).

Torsional Stress

Primary stress caused by twisting action on an aircraft drive shaft or bolt.

Shear Stress

Stress created when two opposing forces try to slide past each other, such as in scissors or clevis pins.

Centre of Gravity (CG)

Point through which the total weight of an aircraft acts vertically downwards.

Mechanical Moment Formula

$$\text{Moment} = \text{Force} \times \text{Perpendicular distance}$$

A Couple

Two equal parallel forces acting in opposite directions but not along the same line, producing pure rotation.

Elasticity

Property of a material that allows it to return to its original shape after deforming forces are removed, such as a rubber band or spring.

Newton's First Law of Motion

An object remains at rest or in uniform motion unless acted upon by an external force (also known as the Law of Inertia).

Kinetic Energy Formula

$$KE = \frac{1}{2} \times m \times v^2$$

Mechanical Advantage Formula

$$\text{Mechanical Advantage} = \frac{\text{Load (Output Force)}}{\text{Effort (Input Force)}}$$

Centripetal Force

Inward force pulling a rotating object toward the centre of its curved path.

Centrifugal Force

Apparent outward force felt by a body moving in a circular path.

Power

Rate of doing work or rate of energy transfer, measured in Watts or Horsepower (Work divided by time).

Bernoulli's Principle

Relationship between fluid velocity and static pressure: as fluid velocity increases, static pressure decreases.

Venturi Airflow Principle

As fluid flows through the constricted neck of a narrow venturi, velocity increases and static pressure drops.

Specific Gravity

Ratio of density of a substance compared to density of pure water at $4\,^\circ\text{C}$.

Viscosity

Measure of a fluid's internal resistance to flow.

Density Formula

$\text{Density} = \frac{\text{Mass}}{\text{Volume}}$ (mass per unit volume).

Celsius to Kelvin Formula

$$K = C + 273.15$$

Rigidity in Space

Gyroscopic property that causes a rapidly spinning wheel to maintain its axis of rotation.

Precession

Gyroscopic property where an applied force produces a reaction $90^\circ$ later in the direction of rotation.

Mechanical Efficiency Formula

$$\text{Efficiency} = \left(\frac{\text{Work Output}}{\text{Work Input}}\right) \times 100\%$$

Atom

Smallest particle of an element that retains all chemical properties of that element.

Molecule

Smallest unit of a chemical compound that retains its chemical identity, consisting of two or more bonded atoms.

Solid

State of matter with a fixed shape and fixed volume, having a rigid molecular structure.

Liquid

State of matter with a fixed volume but no fixed shape, conforming to its container.

Gas

State of matter with no fixed shape and no fixed volume, expanding to fill its container.

Tensile Stress

Stress produced when two pulling forces act away from each other along the same line.

Compressive Stress

Stress produced when two pushing forces act toward each other along the same line.

Strain

Ratio of extension (change in length) to original length under stress.

Yield Point

Maximum stress a material can withstand without undergoing permanent plastic deformation (elastic limit).

Pressure Formula

$$P = \frac{\text{Force}}{\text{Area}}$$

Standard Atmospheric Pressure

ISA standard sea level pressure equal to $1013.25\,\text{hPa}$, $29.92\,\text{inches Hg}$, or $14.7\,\text{psi}$.

Torricellian Barometer

A tube device instrument used to measure ambient atmospheric pressure.

Archimedes' Principle

Principle stating that an immersed object experiences an upward buoyant force equal to the weight of the fluid displaced.

Velocity

Vector quantity that specifies both magnitude and direction of motion.

Acceleration

Rate of change of velocity over time ($a = \frac{\Delta v}{\Delta t}$).

Acceleration Due to Gravity

Standard g-force value near Earth's surface, equal to $9.81\,\text{m/s}^2$ (or $32.2\,\text{ft/s}^2$).

Newton's Second Law Formula

$$F = m \times a$$

Newton's Third Law of Motion

Law stating that for every action there is an equal and opposite reaction.

Friction

Resistance offered to motion when two surfaces slide or roll over each other.

Coefficient of Friction

Ratio of frictional force to normal force between two surfaces, represented by $\mu$.

Potential Energy Formula

$$PE = m \times g \times h$$

Mechanical Work Formula

$$W = F \times d$$

Momentum Formula

$$p = m \times v$$

Impulse Formula

$$\text{Impulse} = \text{Force} \times \text{time}$$

Mechanical Advantage of a Single Fixed Pulley

Equal to $1$ (only changes direction of force, with no force magnification).

Velocity Ratio (VR) Formula

$$\text{Velocity Ratio} = \frac{\text{Distance moved by Effort}}{\text{Distance moved by Load}}$$

Hydrometer

Floating calibrated tube instrument used to measure specific gravity of liquids such as battery electrolyte.

Total (or Stagnation) Pressure Formula

$$\text{Total Pressure} = \text{Static Pressure} + \text{Dynamic Pressure}$$

Static Pressure

Pressure measured by a static port perpendicular to fluid flow.

Conduction

Heat transfer mechanism occurring through direct molecular contact in solids.

Convection

Heat transfer mechanism occurring via bulk movement of fluids (liquids or gases).

Radiation

Heat transfer mechanism occurring via electromagnetic waves without a physical medium.