Brownian motion
- Smoke particles are bombarded by the air
- at any given instant, there are more collisions on one side of the particle than the other
- therefore the change in momentum on each side is unequal
- therefore a force F results.
Ideal gas equation
pV=nRT
p = k/V (at a constant temperature)
When volume V decreases:
- molecules travel less distance before they collide with the container
- therefore there are more collisions every second with the container
- therefore rate of change of momentum increases
- therefore pressure increases.
p = kT (at a constant volume)
When temperature T increases:
- molecules have a greater velocity
- therefore there are more collisions every second with the container
- therefore rate of change of momentum increases
- therefore pressure increases.
pV=(1/3)Nm<c2>
Where
- N = the number of molecules
- m = the mass of each molecule (kg)
- <c2> = the mean square speed
Zeroth law
When you place two bodies in contact and there is no net energy transfer between them:
- they are in thermal equilibrium
- therefore they have the same temperatures.


