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Vibrations and Waves. Properties of Waves. Wave Motion. Medium – the material through which a disturbance travels Mechanical wave – a wave that travels through a deformable, elastic medium. Wave Types. Pulse wave – a single, non-periodic wave
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Vibrations and Waves Properties of Waves
Wave Motion • Medium – the material through which a disturbance travels • Mechanical wave – a wave that travels through a deformable, elastic medium
Wave Types • Pulse wave – a single, non-periodic wave • Periodic wave – a wave whose source is some form of periodic motion • Sine wave – a wave whose source vibrates with simple harmonic motion • Transverse wave – a wave whose particles vibrate perpendicularly to the direction of wave motion
Wave Types • Crest – the highest point above the equilibrium position • Trough – the lowest point below the equilibrium position • Wavelength – the distance between two adjacent similar points of the wave, such as from crest to crest or from trough to trough • Symbolized by the lowercase Greek lambda (λ) • Measured in meters (m) • Amplitude the maximum distance from the equilibrium position • Peak of the crest or valley of the trough • Measured in meters (m)
Wave Types • Longitudinal wave – a wave whose particles vibrate parallel to the direction of wave motion • Sometimes called density or pressure waves • Has stretched and compressed regions • Crests – compressed • Troughs – stretched
Period, Frequency, and Wave Speed • Period – the time it takes a wave to pass through a point • Symbolized by T • Measured in seconds (s) • Frequency – the number of waves (cycles) that pass through a point in one second • Symbolized by f • Measured in cycles per second or Hertz (Hz) • Wave speed – velocity of a wave • Symbolized by v • Measured in meters per second (m/s) • Wave speed = frequency * wavelength • v = fλ • Wave speed = wavelength / period • v = λ/T
Period, Frequency, and Wave Speed • Waves transfer energy • The greater the amplitude of the wave the more energy is being transferred • For mechanical waves, the energy is proportional to the square of the amplitude • Amplitude generally decreases as the wave travels away from the source of the vibration • Called damping