Average Speed in Kinetic-Molecular model

[Ibraheem]

Hello,

In the Kinetic-Molecular model for gas molecules in a container it is assumed that the square of the x-y-z velocity components is the same, how is it possible that we assume this?

 

[Chandra Prayaga]

Why would you feel that one component should be more, or less, than another?
By the way, the assumption is made of the average value of the squares of the components of the velocity.
Also, it is an assumption when the topic is taught at a basic level. In advanced course in statistical physics, it is proved. It is called the theorem of equipartition.

 

[Buzz Bloom]

Hi Ibreheem:

Chandra mentioned

the theorem of equipartition.

You may find the Wikipedia article helpful:

https://en.wikipedia.org/wiki/Equipartition_theorem .​

Regards,
Buzz

 

[Ibraheem]

Thanks for the replies, I can see why this is the case now.