Summary

• Wave characteristics
• Sound waves
• Sound intensity & decibels

• Written Quiz    Timer
  
  
• Doppler effect
  • description
  • video, applet & another applet
  • shock waves and YouTube video
  • acoustic compressor diagrams
    
    Example #1
    
    Example #2
    
  
  
  
  
  
  
  
  
  

kw4
When you drive your car at a constant speed toward a police car, what happens to the frequency of the radar when it bounces off your car?
A. It is shifted higher.
B. It is shifted lower.
C. It stays the same frequency.
Answer















klm
What is the frequency you hear when a 500 Hz siren recedes from you at 25 m/s? Assume v_snd = 343 m/s.
A. 432 Hz
B. 500 Hz
C. 466 Hz
D. 534 Hz
Answer















 



A. It is shifted higher.
The source of the reflected waves is moving toward you, and that produces a Doppler shift to higher frequencies.




















 



C. 466 Hz