Lecture 6: Pressure

[@mathletics6287]

Thank you so much for your lectures. but can you please include your lecture 7(effusion) in this playlist? That knudsen flow is confusing me.

[@vincentmeunier7873]

I'm planning to complete all the missing lectures of the first part of the book by December 2023. I'm also working on lectures on theoretical mechanics...

[@mathletics6287]

but can you tell me why did we integrate from 0 to π/2 to find pressure from the expression (1/2)nvcosθvf(v)sinθdθdv?

[@vincentmeunier7873]

Yes, it is best understood from page number 95 where the solid angle is drawn. You see there that theta sweeps 0 to pi/2 for a solid angle of "theta" opening

[@mathletics6287]

@@vincentmeunier7873Then Why did we neglect other side of the sphere? Is it because the pressure will add up to zero?

[@mathletics6287]

@@vincentmeunier7873 Thank you so much for your lectures. but can you please include your lecture 7(effusion) in this play list? That knudsen flow is confusing me.

[@ilyassoujaddi4569]

Why does the momentum transfer equal 2mvcos@??? I dont understand where did 2 come ?

[@vincentmeunier7873]

It is the change in momentum. It is initially -mv \cos \theta and then mv \cos \theta after the molecule hits the wall. Thus, the change in momentum is thus 2 mv \cos \theta

[@ilyassoujaddi4569]

@@vincentmeunier7873 thanks a lot ... ur fan from morocco. Je sais que vous êtes belge et ainsi vous parler le français ...ça se voit surtout sur ton accent... vraiment vous faites un trop honneur pour votre pays ...