Can someone explain to me these equations of sound waves?

AI Thread Summary
The discussion centers on the equations related to sound waves, specifically I = 1/2 ρ v ω² A² and β = 10dB * log(I/I0). Participants clarify that "I" represents sound intensity, while "A" likely refers to area. They confirm that ρ is the density of air, v is the velocity of sound (343 m/s), and ω is the angular frequency (2πƒ). The second equation calculates sound intensity in decibels relative to a reference intensity, highlighting the logarithmic nature of power ratios in sound measurements.
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I = 1/2 ρ v ω2 A2

I don't know what "I" is nor do I know what "A" is but it has to do with sound waves.
May you also please correct me if I am wrong but is:
ρ = density of air
v = velocity of sound = 343 m/s
ω = angular frequency of the sound wave = 2πƒ

And also may you please answer what is this second equation?:

β = 10dB* log(I/I0) ?
 
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Blockade said:
I = 1/2 ρ v ω2 A2

I don't know what "I" is nor do I know what "A" is but it has to do with sound waves.
May you also please correct me if I am wrong but is:
ρ = density of air
v = velocity of sound = 343 m/s
ω = angular frequency of the sound wave = 2πƒ

And also may you please answer what is this second equation?:

β = 10dB* log(I/I0) ?
I looks to be the sound Intensity. The last equation looks to be the change in Intensity in dB as the sound wave propagates...

Can you post links to where you got the equations from?
 
Do a dimensional analysis.You may find a (time)^-3 term, which is a hint. Just as a wild guess, try units for area for A... then look up the dimensions for power.
Quite often, power ratios are expressed as a logarithm.
 
##\omega## stands for angular frequency which is ##= 2 \pi f## where f ins the frequency.
##I## stands for intensity which is ##= power/area##
##\beta## stands for decibel level which is a relative loudness

This Rutgers lab gets into db measurements and describes the last equation in your post that converts sound intensity relative to a standard baseline intensity to decibels:

https://www.physics.rutgers.edu/ugrad/301/PS08_Intensity_New.pdf

The HyperPhysics book has a description of these equations in great detail:

http://physics.info/intensity/
 
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