L25 波 Superposition


Superposition of 2 Waves on a String

Pre-Amble

  • Today all milestones part A Retry.
  • Finish Traveling Waves (Doppler)

🔑 Superposition: Dtotal(r,t) = Σ Di(r,t)

e.g. if 2 waves, we have wave interference
D1(x,t) = A1 cos(k1x - ω1 t)
D2(x,t) = A2 cos(k2x - ω2 t)
Below we assume A2=A1
k2 = k1, ω2 = - ω1
→ Standing Waves
k2 = k1, ω2 = + ω1
→ Interference
k2 ~ k1, ω2 ~ + ω1
→ Beats

Standing Waves & Resonance Effect

ViewGraphs: Knight Chapter 21


Normal Modes
Normal Modes
(Standing Waves)
Sound
Sound Waves
Interference

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