Question is inspired by a recent burst of perpetuum mobile-type questions. It would be nice if one could simply discard them all (or at least the huge class that assumes some kind of perfect vacuum to eliminate friction) by an argument that shows it's impossible to create a perfect vacuum. Intuitively, I have some hope that there will be a thermodynamics/statistical mechanics argument that we can never even eliminate air friction completely, thereby ruling out all these elaborate constructions requiring specific arguments from the get-go. My question is therefore twofold:
- Does it take infinite energy to create a perfect vacuum (in a macroscopic box)?
- If yes, can you include a derivation? If no, can you give an explicit construction with a finite amount of work being done?