BOFH: Impatience "You’re not listening to me!" the Boss snaps. "Hmm?" "You’re not listening to me!" "Course I am," I say distractedly. "What did I say then?" "The users are unhappy." "I… What about?" the Boss asks, temporarily foiled by my Geller-like guesswork. "Some user thing or the other – their stupidity, the computer doing what …
erm, actually no that's a lie, I LOVE being pedantic, it's everyone else who hates it :)
Anyway back to my point, it's E=mc^2 (superscript 2, not subscript 2), and to be precise it is in that case (upper case E, lower case m and c) if I remember my physics correctly.
It is SO true though. Myself, I prefer Freecell, but there is nothing more anoying than someone trying to help you when playing solitair
As everyone knows every BOFH started out life as a PFY at one time or another. Therein lies a problem. Yes, we need one, but if they get too much knowledge, the castle coup takes place at some time. It happens when the PFY gets the BOFH (or the pretender to BOFHdom) relieved at some time.
Yes, I was a PFY at one time (it was the 60's). Then I became a BOFH, and then relieved. Changing of bosses, did me in.
No, you don't have to anihilate the full atom. If a U-235 nucleus decays into a smaller nucleus, only the difference in mass between the former and latter nucleus is converted into energy (though remember to take account of the mass of any new particles in the new configuration).
>>Correct me if I wrong, but I thought atomic bomb comes nowhere near E=mc^2. Only by anihilation of particle and antiparticle you do get all the energy released by this formula. No?
If you check the weights in an atomic table, they are not exact integers. So in a reaction such as
235U + 1 neutron -> 2 neutrons + 92Kr + 142Ba + ENERGY
the atoms don't have exact integer weights of 235, 92, and 142 (because of binding energy). instead this works out as:
235.0439231 + 1 -> 2 + 91.9261528 +141.9164482+ ENERGY
energy = 235.0439231 - 91.9261528 + 141.9164482 - 1
energy = 0.201322 (atomic mass units)
That 0.201 of missing mass after the reaction shows up as energy based on E=MC^2. It's not *all* of the energy in the 235U nucleus, but it's still a pretty big valua and is based on E=MC^2.
In periodic tables are averages of the different atomic masses of the different isotopes of the element, weighted for their relative abundance. To get the actual relative atomic mass you need to look a bit further than your bog standard periodic table.
http://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=
Hmm we need a science icon
Efros
very very briefly. atomic bombs, fusion or fission, work on the change in binding energy which holds the nucleus together. Light nuclei (H, He, Li etc) when combined release energy, the heaviest (U, Pu) release energy when broken up. IIRC, Iron is the most "efficient" nucleus in terms of mass vs binding energy.
but all this is from 20 year old memories of physics.
> In periodic tables are averages of the different atomic masses of the different isotopes of the element, weighted for their relative abundance. To get the actual relative atomic mass you need to look a bit further than your bog standard periodic table.
Good point. But I did check the per-isotope weights on a per-isotope web site, so the posted numbers should be correct, I think.
"But is it not E=mc^2 / 1 - (v^2/c^2)? Something to do with the liberation of kenetic energy when a moving partical is anihilated as well as the energy from the mass itself."
Order of operations, gentlemen. Either the "/ 1" is superfluous, or that formula should read E=mc^2 / (1 - (v^2/c^2)). Quite a difference there...
The proper equations are
E = MC^2 where M is the current mass of the object
or
E = mC^2/(1-V^2/C^2) where m is the rest mass of the object
The second equation is simply a way of deriving the energy (or indirectly the active mass) of an moving object.
The key understanding is that energy and mass are in fact the same thing. Once you pick up that part of it things all start to make more sense.
Also, the equations are from Einstein's Theory of Special Relativity (the first one) rather than General Relativity. Special Relativity only properly handles objects travelling with constant velocity in free space. Once you introduce any sort of acceleration you need General Relativity and the world gets a whole lot more complicated.
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