PowerPoint Presentation

P H Y S I C SChapter 7: Waves and Vibrations

Section 7D: Wave Behavior and SoundBell RingerTell me about this wave: a. how many waves? b. wavelength, c. amplitude d. label crest and trough e. period f. frequency g. speed (v=f)

t=10s40cm50cm

1) Fixed End Reflection: Reflected pulse is inverted

Boundary BehaviorReflected PulseIncidentPulseBEFOREAFTER

2) Free End Reflection: Reflected pulse is not inverted

Boundary BehaviorReflected PulseIncidentPulseBEFOREAFTER

Wave Interference1) Constructive Interference: Amplitudes of wave pulses add togetherBeforeDuringAfterA + BABAB

Wave Interference2) Destructive Interference: Amplitudes of wave pulses subtractBeforeDuringAfterA - BABABStanding WavesResults from interference of multiple waves

Nodes destructiveAnti-Nodes constructive

Slinky DemonstrationBoundary Behavior: 1) Fixed End Reflection 2) Free End ReflectionInterference: 3) Constructive 4) Destructive 5) Standing Waves

Sound WavesSound waves are longitudinal waves

RarefactionCompressionBeatsAlternating constructive and destructive interference between two sound waves of different frequencies

Beats Applet

Doppler EffectDue to a moving source or observerCauses apparent shift in frequency

Doppler Effect Applet

24 Hz Wave + 24 fps Camera