Relativity of Mass or 'Weight' ?

[toe21k]

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Hydogen's Mass or 'Weight' is negative (i.e. less than 0 kg)


Given a Balloon filled with 'Hydrogen'...


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[LURCH]

Originally posted by toe21k
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Hydogen's Mass or 'Weight' is negative (i.e. less than 0 kg)

Only if we first set the mass or weight of air as our "0" point. In a vacuum, or even a near-vacuum like on the Moon or at very high altitude, a hydrogen balloon will fall.

 

[HallsofIvy]

That depends upon the strength of balloon I suspect (I confess I have never actually done the experiment!) that a standard helium filled balloon (filled with, say, 1/10 the helium one would normally put in it), on the moon, would not burst but would fall as Lurch said.


By the way, the original post:
[quoge]Hydogen's Mass or 'Weight' is negative (i.e. less than 0 kg)[/quote]
is non-sense for a variety of reasons.

Hydrogen does not have a specific weight or mass: it has density measured (mass-density) of kg/m³ or (weight-density) Newtons/m³.

Nothing has negative density (or weight or mass) pretty much by definition.

 

[toe21k]

So as Zero...

i.e. 'Nothing' has Zero density (or weight or mass...etc.).

http://superstringtheory.com/forum/partboard/messages20/46.html

 

[toe21k]

Everybody thought that the Photons, like Neutrinos were 'massless'...



https://www.physicsforums.com/showthread.php?s=&threadid=9764

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[HallsofIvy]

And the point of the last two posts was?

 

[Nereid]

kx21 - folk on superstringtheory.com thought she was a bot

For those who are interested, a look at some of the threads on the (now defunct?) superstringtheory.com forum may give some insight into kx21 and what meaning her posts have.

There was, IIRC, an exchange between two old hands on that forum, discussing whether kx21 was real, or just a bot.

Of course, toe21k may have no relation whatsoever to kx21 ...