Acoustics and Sound Fundamentals

Vocabulary flashcards covering introductory physics, acoustics, motion laws, sound transmission, wave mechanics, and waveform properties based on lecture notes.

Physics

The science of matter, energy, motion, and force.

Acoustics

The study of sound, including its production, transmission, energy, effects, and perception.

MKS System

A metric measurement system that measures distance in meters, mass in kilograms, and time in seconds.

CGS System

An older metric measurement system that uses smaller units: centimeters for distance, grams for mass, and seconds for time.

Mass

The amount of matter in an object, measured in grams ($\text{g}$) or kilograms ($\text{kg}$).

Volume

The quantity of three-dimensional space occupied by a liquid, solid, or gas, measured in liters.

Density

The mass of a substance per unit volume, measured in $\text{g/cm}^3$.

Stiffness

A material property defined as the resistance to deformation.

Elasticity

A material property defined as the ability to spring back after deformation.

Hooke's Law

A physical law stating that the change in length of a material is proportional to the force applied to it.

Speed

The distance traveled per unit time.

Velocity

The distance traveled per unit time in a specific direction.

Momentum

A measure of a mass in motion.

Inertia

The resistance of an object to changes in its motion.

Newton's First Law of Motion

Also known as the Law of Inertia; states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and direction unless acted upon by an unbalanced force.

Newton's Second Law of Motion

States that the acceleration of an object is proportional to the force acting on it and inversely proportional to its mass ($F = ma$).

Newton

The unit of force ($\text{N}$), defined as the amount of force necessary to accelerate $1\,\text{kg}$ of mass at $1\,\text{m/s}^2$.

Newton's Third Law of Motion

States that for every action (force), there is an equal and opposite reaction ($F_{AB} = -F_{BA}$).

Speech

Defined by Stetson (1928) as "movement made audible"; a motor behavior that produces variations in air pressure.

Brownian Motion

The constant, rapid, random movement of air molecules within a small area when at rest.

Sound Production Elements

The three required components for producing sound: an energy source (event), a vibrating body, and a transmitting medium.

Transmitting Medium

Interconnected particles (solids, liquids, or gases) through which sound travels.

Oscillation

The back-and-forth motion of a particle or object around its rest position.

Characteristic Frequency

Also known as natural or resonant frequency; the specific frequency at which a vibrating body naturally tends to vibrate for its mass and structure.

Simple Harmonic Motion

Also known as sinusoidal motion; vibratory motion that produces sound and causes the sensation of a pure tone in the listener.

Pure Tone

A sound consisting of a single frequency produced by simple harmonic motion.

Longitudinal Wave

A wave in which medium particles oscillate back and forth parallel to the direction of wave movement.

Emergent Phenomenon

A process in which a sound wave transports energy across a medium through particle disturbances without individual particles traveling great distances.

Waveform

A graphical plot showing the amplitude of a signal over time.

Amplitude

The displacement of particles from rest, which is directly related to the magnitude of sound.

Wavelength

Expressed as $\lambda$; the distance a sound wave travels during one complete cycle of vibration, measured in feet or meters.

Cycle

One complete repetition of a periodic wave or vibratory motion.

Frequency

The rate of vibration measured in cycles per second (cps) or Hertz ($\text{Hz}$).

Hertz

The unit of measurement for frequency ($\text{Hz}$), equivalent to one cycle per second.

Period

The time taken to complete one single cycle of vibration.

Condensation

Also called compression; a region in a longitudinal wave where medium particles are pressed tightly together, resulting in increased pressure.

Rarefaction

A region in a longitudinal wave where medium particles are spread apart, resulting in decreased pressure.