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-   -   Weightless Vacuum Container maximum height (http://www.physicsforums.com/showthread.php?t=660204)

cantRemember Dec21-12 06:02 AM

Weightless Vacuum Container maximum height
 
Assume you have a weightless constant volume container "filled with" vacuum. If you let it float in the atmosphere, how "high" would it go? I guess at some point Archimedes' principle should fail. What do you think?

sophiecentaur Dec21-12 06:32 AM

Re: Weightless Vacuum Container maximum height
 
Hi
If this thing is completely 'weightless' (a thought experiment) then there is no limit to where it would end up. It would always be displacing some weight of atmosphere. The atmosphere of a totally isolated Earth 'goes on' for ever and there would always be a pressure difference between nearer and more distant sides of the box which would produce an outward force .
As real high altitude balloon flights show, the practical limit is around 50km; not very far at all but of course that's not a 'weightless' box of vacuum.


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