The Doppler Effect (in general)

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The discussion centers on the Doppler effect, specifically why the observed frequency of a wave increases as the source approaches and decreases as it recedes. It clarifies that the relative velocity between the observer and the source changes continuously, even if the source is initially heading straight toward the observer. The observed frequency is not constant because it varies based on the changing distance and angle of approach, leading to a non-linear frequency shift. It is noted that at the point of closest approach, the observed frequency equals the emitted frequency, but the frequency continues to change as the source moves away. Overall, the Doppler effect is influenced by the relative motion of the source and observer, making it a complex phenomenon rather than a simple constant shift.
  • #61
I wasn't talking about the 'radial' or 'transverse' direction----we can have these components of relative velocity whatever direction(north,south,east) the motion is in.

I was actually reffering to the importance of 'position' of source and observer in the analysis.Besides,as long as we know the relative velocity,and the direction of it,it doesn't matter whether it's north or south,what matters is the direction w.r.t each other (moving towards or moving away)--we can choose north-south directions as we please.

The line I'm referring to is on the page given below,in the third last paragraph of the section 'Analysis'.

http://en.wikipedia.org/wiki/Doppler_effect
 
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  • #62
Time reversal?Iwould wwant to know more on it
 
  • #63
Urmi Roy said:
I wasn't talking about the 'radial' or 'transverse' direction----we can have these components of relative velocity whatever direction(north,south,east) the motion is in.

I was actually reffering to the importance of 'position' of source and observer in the analysis.Besides,as long as we know the relative velocity,and the direction of it,it doesn't matter whether it's north or south,what matters is the direction w.r.t each other (moving towards or moving away)--we can choose north-south directions as we please.

The line I'm referring to is on the page given below,in the third last paragraph of the section 'Analysis'.

http://en.wikipedia.org/wiki/Doppler_effect
That wiki paragraph is referring to the fact that in a more complete analysis one must take the travel time of the signal into account (from source to observer) in order to determine what the observer actually observes at any given time. To do that requires knowing the position of the source at the time of emission, not just its direction of motion.
 
  • #64
Thanks,Doc Al,I understand now.
 
  • #65
Waves farther from the source lag behind those closer to it.So if you have positive radial velocity greater than the speed of sound you hear the song played backwards
That's time reversal
 

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