Can someone explain to me these equations of sound waves?

In summary, sound travels through air in the form of waves, created by vibrations of an object. The equation for calculating the speed of sound is v = λ x f, where v is the speed of sound, λ is the wavelength, and f is the frequency. The frequency of a sound wave is directly proportional to its pitch, with higher frequencies resulting in higher pitches. The wavelength of a sound wave can be calculated using the equation λ = v/f. Amplitude and intensity are both measures of the strength of a sound wave, with amplitude measuring the height and intensity measuring the loudness.
  • #1
Blockade
68
0
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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  • #2
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?
 
  • #3
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.
 
  • #4
##\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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1. How does sound travel through air?

Sound travels through air in the form of waves. When an object vibrates, it creates sound waves that travel through the air. These waves cause the air particles to vibrate, which in turn creates a series of compressions and rarefactions that travel through the air until they reach our ears.

2. What is the equation for calculating the speed of sound?

The equation for calculating the speed of sound is v = λ x f, where v is the speed of sound in meters per second, λ is the wavelength of the sound wave in meters, and f is the frequency of the sound wave in Hertz. This equation is known as the wave equation and is used to calculate the speed of sound in different mediums.

3. What is the relationship between frequency and pitch in sound waves?

The frequency of a sound wave is directly proportional to its pitch. This means that the higher the frequency of the sound wave, the higher the pitch will be perceived by our ears. For example, a sound wave with a frequency of 200 Hz will have a higher pitch than a sound wave with a frequency of 100 Hz.

4. How do you calculate the wavelength of a sound wave?

The wavelength of a sound wave can be calculated using the equation λ = v/f, where λ is the wavelength in meters, v is the speed of sound in meters per second, and f is the frequency of the sound wave in Hertz. This equation can be rearranged to find the wavelength when given the speed of sound and frequency.

5. What is the difference between amplitude and intensity in sound waves?

Amplitude and intensity are both measures of the strength or energy of a sound wave. Amplitude is the maximum displacement of a particle from its rest position, while intensity is the amount of energy passing through a unit area per unit time. In simpler terms, amplitude measures the height of the sound wave, while intensity measures its loudness. Amplitude is measured in units of distance, while intensity is measured in units of power per unit area.

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