Exam 2 Review

Molecules

Particles that make up every medium and are always in motion, even at rest.

Elasticity

The property of a material that describes its ability to return to its original shape after being deformed; also known as elastic restoring force.

Inertia

The property of matter that causes it to resist changes in its state of motion; related to mass.

Sound Propagation

The transmission of a disturbance (or pressure wave) through a medium.

Frequency

The number of cycles per second, measured in Hertz (Hz); calculated as f = 1/Period.

Wavelength (λ)

The distance of one complete cycle of a wave; calculated as Wavelength = Speed/Frequency.

Diffraction

The bending of sound waves around obstacles, which is more pronounced for longer wavelengths.

Simple Harmonic Motion

The motion of particles as they oscillate around their rest position in a periodic manner, often represented as a sine wave.

Decibels (dB)

The unit of measure for amplitude and sound intensity level.

Fundamental Frequency

The lowest frequency component of a complex wave.

Harmonic Frequencies

Integer multiples of the fundamental frequency (e.g., F₀, 2F₀, 3F₀).

Resonance

The tendency of a system to vibrate with greater amplitude at specific frequencies.

Aperiodic Waves

Waves that show irregular, non-repeating patterns in waveform view.

Atmospheric Pressure

The pressure exerted by the weight of air in the atmosphere.

Sound Pressure Level (SPL)

A measure of sound pressure, calculated as 20 log(P/P₀) with P₀ as the reference pressure of 20 μPa.

Sound Intensity Level (SIL)

A measure of sound intensity in decibels, calculated as 10 log(I/I₀) with I₀ as the reference intensity level of 10⁻¹² watts/m².

Compliance

The measure of how much a material deforms under a given pressure or force; inversely related to stiffness.