Hello, I am having some difficulty following the method for finding an equation for an ideal gas. There are a few different forms, but I'm proving 1. For an indiviual particle of a gas in a cube container side length L, it is travelling with a velocity of u1 on the x axis (its x component of velocity is u1). This collides with one surface and rebounds elastically. This would have a velocity -u1 as no kinetic energy was lost. I want to find the force this particle exerts on the wall by its x component. So to find Force i would use rate of change of momentum. the distance before it collides with the surface is 2L. so time = 2L/u1.(adsbygoogle = window.adsbygoogle || []).push({});

so for my equation I now have force = change of momentum

2L/u1

change in momentum equals mv - mu. according to the principal of conservation of momentum would i be correct in saying mv - mu = 0 ?? (v = final velocity, u = initial)

if so, -mu1 - mu1 is the change in momentum -2mu1. Now i was told the change in momentum should be equal to 2mu1. Which leaves me with a problem. Does -2mu1 = 0 ??? if so can i easily get 2mu1 by adding it to both sides? which gives me a positive change in momentum. Seems odd to me, can someone please explain that and if that would be the correct way of doing it? I have no problems getting the P = 1/3 rho (mean velocity squared) equation from that, but the change in momentum is bothering me. I could just remember 2mu1, but I would rather know how to work it out properly. Any help is very much appreciated, thanks

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# Homework Help: Gas Pressure

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