Particle acceleration
In acoustics, particle acceleration is the acceleration (rate of change in speed and direction) of particles in a sound transmission medium. When sound passes through a medium it causes particle displacement and as such causes changes in their acceleration.
The acceleration of the air particles of a plane sound wave is given by:
| Symbol | Units | Meaning | 
|---|---|---|
| a | m/s2 | particle acceleration | 
| v | m/s | particle velocity | 
| δ | m, meters | particle displacement | 
| ω = 2πf | radians/s | angular frequency | 
| f | Hz, hertz | frequency | 
| p | Pa, pascals | sound pressure | 
| Z | N·s/m3 | acoustic impedance | 
| J | W/m2 | sound intensity | 
| E | W·s/m3 | sound energy density | 
| Pac | W, watts | sound power or acoustic power | 
| A | m2 | area |