The discussion revolves around the Doppler effect and its implications on frequency changes when a source of sound is moving relative to an observer. Participants are exploring the relationship between relative velocity and observed frequency, particularly in the context of a source moving towards a listener.
Some participants have provided insights into the correct application of the Doppler formula, noting the importance of the source's velocity in the denominator. There is ongoing exploration of the qualitative understanding of why the relative motion of the source and observer matters, with no clear consensus reached yet.
Participants are grappling with the nuances of the Doppler effect, particularly the distinction between the velocities of the source and the observer, and how these relate to the medium (air) through which sound travels. There is mention of the need to review the derivation of the formula for deeper understanding.
What does the Doppler formula give you for the observed frequency when the source is moving? Not sure what you mean by "total velocity"--realize that the source is moving towards the listener.PsychonautQQ said:I don't understand how it increases it's frequency by a factor of 10, I mean the total velocity goes from 1 to 1.9, therefore It seems like it should increase from 1kHz to 1.9kHz. Why is my 'common sense' wrong?
No.PsychonautQQ said:frequency receiver = (velocity sound + velocity sender) * frequency sender
with velocity of sound = c and velocity of sender = .9c, It seems the frequency received is 1.9 the original frequency. No?
Note that relative velocity (of source and observer) doesn't enter into the Doppler formula (at least for sound). The speeds are relative to the air. And that a moving source differs from a moving observer. (Compare the two cases, even for the same speed.)PsychonautQQ said:Okay so the correct Doppler effect the source is in the denominator, I don't understand qualitatively why it matters though. Whether it's the receiver or sender that's movie, the relative velocity between them is going to be the same?