Lecture 19: Vibrations and Waves

This set of flashcards covers vocabulary and key concepts from Lecture 19, including wave properties, types of motion, interference, standing waves, and the Doppler effect.

Wave

A periodic oscillation that transfers energy from one place to another through space or a medium.

Vibrations

Oscillations that remain fixed in one location rather than traveling through space.

Periodic oscillation

A repeating pattern of motion that gives rise to various wave properties.

Crest

The high point on a wave.

Trough

The low point on a wave.

Equilibrium value

The center position of a wave, representing the value of the wave if it were at rest.

Wave amplitude

The maximum displacement of a wave from its equilibrium position.

Wavelength

The distance between two identical points on a wave, such as from crest to crest, represented by the Greek letter $\lambda$.

Ripple tank

An apparatus containing a shallow tank of water used to study wave properties by generating ripples with moving pieces.

Period

The amount of time it takes for one complete oscillation to occur, represented by the symbol $T$ and measured in seconds.

Frequency

The number of oscillations that occur per second in a wave, represented by the symbol $f$ and measured in Hertz ($Hz$).

Hertz

The unit of frequency where $1\,Hz$ is equal to $1$ divided by a second ($1/s$).

Wave speed

The speed at which a wave moves, calculated using the equation $v = \frac{\lambda}{T}$ or $v = \lambda \times f$.

Longitudinal wave

A wave in which the vibrations travel in the same direction as the wave itself.

Transverse wave

A wave in which the vibrations travel perpendicular to the direction of the wave's motion.

Torsional wave

A type of wave involving a twisting motion back and forth in a periodic manner, such as the wave that caused the Tacoma Narrows Bridge to collapse in $1940$.

Interference

The phenomenon where two or more waves overlap in the same space and their values add together.

Interference pattern

The resulting shape generated when multiple waves interfere, determined by wavelength and source proximity.

Constructive interference

A situation where waves overlap such that crest meets crest and trough meets trough, resulting in a wave with greater amplitude.

Destructive interference

A temporary condition where waves overlap such that crest meets trough, causing the waves to cancel out and result in zero amplitude.

Standing waves

Waves that oscillate in time but appear fixed in space, created by the interference of two waves with equal amplitude and frequency traveling in opposite directions.

Nodes

The specific locations on a standing wave that remain fixed and do not oscillate.

Antinodes

The locations on a standing wave that oscillate between minimum and maximum values.

Harmonic

A specific mode of a standing wave characterized by the number of antinodes it contains.

Fundamental mode

Another name for the first harmonic of a standing wave.

Doppler effect

The change in the observed frequency and wavelength of a wave due to the relative motion between the source and the observer.

Sonic boom

A shockwave created by the overlapping of wavefronts when an object travels faster than the speed of sound.