Mechanical Waves Review

Waves

Transfer energy without transferring mass

Mechanical Waves

Waves that exist as an vibration of a physical medium (e.g. water, sound)

Electromagnetic Waves

Consist of electric and magnetic fields; can travel through a vacuum (do NOT require a medium)

Transverse Waves

A wave in which the particles of the medium vibrate PERPENDICULAR to the direction the wave is traveling.

Longitudinal Waves

A wave in which the particles of the medium vibrate PARALLEL to the direction the wave is traveling.

Wavelength

The distance between consecutive, corresponding points (e.g. peak of crest to peak of crest, beginning of crest to beginning of the next crest)

Frequency

The number of complete waves per second. Frequency = (# of waves)/time

Period

The time for one complete wave. Period = time/(# of waves)

Amplitude

The height of a wave, measured from the mid-line up to the crest OR down to the trough.

Mechanical Wave Energy

Directly proportional to amplitude

Constructive Interference

Maximum at 0 degree phase difference (e.g. crest lined up with crest, trough lined up with trough)

Destructive Interference

Maximum at 180 degree phase difference (e.g. crest lined up with trough)

Standing Wave

A pattern of wave crests and troughs that appear to remain stationary. Caused by two identical waves traveling in opposite directions.

Node

The part of a standing wave where destructive interference occurs

Antinode

The part of a standing wave where constructive interference occurs

Doppler Effect

The apparent shift in a wave's frequency/pitch due to relative motion between the source and observer

Wave Source and Observer Get Closer

Observed frequency is higher than emitted

Wave Source and Observer Get Farther Away

Observed frequency is lower than emitted

Diffraction

The spreading out of a wave beyond a barrier

Natural Frequency

The particular frequency at which an object naturally vibrates when disturbed

Resonance

The spontaneous vibration of an object at its natural frequency due to an incident wave of the same frequency

Periodic Wave

A wave caused by a repetitive oscillation.

Pulse

A disturbance in a medium caused by a single oscillation.