# How to modify kinetic gas theory to work for macroscopic particles? (2D)

For the first time I framed a question on my own when I was recently playing carrom pool with my cousin and a striking thought ran across my mind!

I was thinking if a square frame is fixed rigidly on a frictionless floor and contains $$N$$ identical TENNIS balls or discs or whatever of mass $$m$$ within it & if the balls are moving randomly with a constant speed v and colliding with each other and the walls of the frame. Also lets assume they collisions are perfectly elastic. Then I was wondering what would be the average force on any 1 of the vertical sides of the frame!

This thread gives hints on how to calculate the situation for 2D situation, keeping all assumptions of kinetic gas theory same. But, how would one modify kinetic gas for macroscopic particles? (In this case discs)

• @TrystwithFreedom Thanks dude, that wikipedia link helped, I didnt know we could write it as PA, but bro my real doubt is, we have BALLS (no pun intended), not gas molecules, so is this logic which I used even correct? May 17, 2023 at 13:22
• @TrystwithFreedom No bro I meant like Big say tennis balls May 17, 2023 at 13:44
• @TrystwithFreedom Can we talk privately, is there a feature for that? May 17, 2023 at 13:47
• I think this is only true for an ideal gas where size of molecules is negligible. Also, I don't think increasing the temperature of the system in this case will increase the kinetic energy of the balls themselves May 17, 2023 at 14:03
• Moreover, I feel like this is a chaotic system (a deterministic system that is difficult to predict). But possibly, you can use the ideas from the derivation of the kinetic gas equation to have a roughly approximated view of this. May 17, 2023 at 14:14