Pressure from Kinetic Theory (P = (1/3)nm·v²_rms = (1/3)ρ·v²_rms)
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P = (1/3)nm·v²_rms = (1/3)ρ·v²_rms
What each symbol means
| Symbol | What it stands for |
|---|---|
| P | Pressure of gas (Pa) |
| m | Mass of one molecule (kg) |
| n | Number density = N/V (molecules per m³) |
| ρ | Mass density = nm (kg/m³) |
| v²_rms | Mean of squared speed (m²/s²) |
When to use this
Derived assuming elastic collisions, isotropic velocity distribution, negligible molecular volume. The 1/3 factor arises from isotropy: v²_x = v²_y = v²_z = v²/3.