What is the relationship between particle velocity and sound waves in air?

In summary, a sound wave with a frequency of 500 Hz and a wavelength of 0.68 m can cause an air molecule to move at a particle velocity, which is the physical speed of a parcel of fluid as it moves back and forth in the direction of the sound wave. The particle velocity should not be confused with the speed of the wave or the velocity of individual molecules. It is usually measured using a logarithmic decibel scale called particle velocity level. It is important to provide background and detail when asking a question to receive a satisfactory and scientifically accurate response.
  • #1
morgan8222
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I have an air molecule moving because of a sound wave.

f of sound wave = 500 Hz
wavelength of sound wave = 0.68 m

How fast is the air molecule moving in its equilibrium position?

Is it in equilibrium at V max? Would this be where the position = 0?
 
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  • #2
morgan8222, here is some information about sound in air. Note that it does not directly answer your question because it refers to a "parcel of air" and NOT to an individual air molecule.

"Particle velocity is the velocity v of a particle (real or imgined) in a medium as it transmits a wave. In many cases this is a longitudinal wave of pressure as with sound, but it can also be a transverse wave as with the vibration of a taut string.
When applied to a sound wave through a medium of a fluid like air, particle velocity would be the physical speed of a parcel of fluid as it moves back and forth in the direction the sound wave is traveling as it passes.
Particle velocity should not be confused with the speed of the wave as it passes through the medium, i.e. in the case of a sound wave, particle velocity is not the same as the speed of sound. The wave moves relatively fast, while the particles oscillate around their original position with a relatively small particle velocity. Particle velocity should also not be confused with the velocity of individual molecules.
In applications involving sound, the particle velocity is usually measured using a logarithmic decibel scale called particle velocity level."
http://en.wikipedia.org/wiki/Particle_velocity

May I ask the source of your question? Members here in Physics Forums always want to be sure a person gets a satisfactory and scientifically correct response to her question. If you can provide the background (origin) and more detail of the exact conditions, perhaps a member can give the exact response you need.
 
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What is equilibrium of air molecule?

Equilibrium of air molecule refers to the state in which the number of air molecules entering a given area is equal to the number of molecules leaving that area. In other words, it is a state of balance in the movement of air molecules.

Why is equilibrium of air molecule important?

Equilibrium of air molecule is important because it ensures that the concentration of air molecules remains consistent and stable. This is essential for maintaining a healthy and livable environment.

How is equilibrium of air molecule maintained?

Equilibrium of air molecule is maintained through various factors such as temperature, pressure, and concentration gradients. These factors influence the movement of air molecules and help to balance their distribution.

What happens if equilibrium of air molecule is disrupted?

If equilibrium of air molecule is disrupted, it can lead to imbalances in the concentration of air molecules, which can have negative effects on the environment and organisms living within it. This can result in changes in weather patterns, air quality, and other environmental factors.

Can equilibrium of air molecule be affected by human activities?

Yes, human activities such as burning fossil fuels, deforestation, and industrial processes can disrupt the equilibrium of air molecule by releasing large amounts of gases into the atmosphere. These gases can alter the concentration and movement of air molecules, leading to imbalances and potentially harmful effects on the environment.

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