Beat frequency and Doppler shift

AI Thread Summary
The discussion centers on the application of beat frequency and Doppler shift equations, specifically with a beat frequency of 4 Hz and a carrier frequency of 260 Hz. Participants express confusion about integrating these frequencies to determine the perceived sound when running towards a speaker, questioning the conditions necessary to hear no beat. The concept of achieving no beat is linked to the frequencies f1 and f2 being equal, but this raises further questions about its implications for calculating running speed. Clarification is sought on the conditions required to hear no beat, emphasizing the need for equal frequencies from the speakers. The conversation highlights the complexities of sound perception in relation to motion and frequency changes.
dawn-
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Homework Statement
Angharad stands midway between two speakers with frequencies 258 Hz and 262 Hz. The speed of sound in the air is 340 m/s. If Angharad does not want to hear beats, how fast and in which direction should she run so that the frequencies she hears from the two speakers are the same? What is this frequency she hears?
Relevant Equations
λ=vT
|f1-f2|= fb
(f1+f2)/2 = fc
(v±vo / v±vs)(f) = fo
where v = speed of wave, vo = speed of observer, vs = speed of source, f = frequency of wave, fo = frequency observed
I found the beat frequency to be 4 Hz and the carrier frequency to be 260 Hz, but I'm not sure how to apply them to the solution/integrate the doppler and beat frequency equations?
 
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dawn- said:
I found the beat frequency to be 4 Hz and the carrier frequency to be 260 Hz, but I'm not sure how to apply them to the solution/integrate the doppler and beat frequency equations?
Seems to me there are infinitely many solutions if able to run in any direction, so assume it is directly towards one speaker. If the running speed is v and the speed of sound is c, what two frequencies will be heard?
 
haruspex said:
Seems to me there are infinitely many solutions if able to run in any direction, so assume it is directly towards one speaker. If the running speed is v and the speed of sound is c, what two frequencies will be heard?
I'm still real lost... I first thought "hearing no beat" means I should set the beat frequency to zero because f1 needs to equal f2 for that to be true, but that doesn't make any sense if I use that to try and solve for running speed..? What conditions need to be met in order to hear no beat?
 
dawn- said:
hearing no beat" means I should set the beat frequency to zero because f1 needs to equal f2 for that to be true, but that doesn't make any sense if I use that to try and solve for running speed..
Why doesn't it make sense? Anyway, please put that aside for the moment and try to answer the question I asked in post #2.
dawn- said:
What conditions need to be met in order to hear no beat?
You are told that:
"so that the frequencies she hears from the two speakers are the same"
 
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