Really, I need to get my own PFY. So much energy, so useful.

Cheers,

Mike

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?

Given the typical energy output I observe every day from my 7yo son, I would have to say that the PFY was quite restrained in his response.

Lucky me, I already do. :D

on earth is the BOFH story posted under the bootnotes heading instead of its own BOFH heading? I reckon its an evil plot to make it more difficult for us to get our weekly BOFH fix.

Fortunately, there are safer computer games....such as nethack.

Dave

P.S. I'll get me coat. It's the one over there somewhere that's not moving (Heisenberg and all that).

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.

Personally, I like the idea that Energy is equal to Mass times two Carbon atoms. It makes things nice and easy.

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).

E^2 = (mc^2)^2 +(pc)^2 where p is the momentum of the particle. E=mc^2 is the case with zero momentum.

>>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.

Too right, I suspect a plot by the boss to have past episodes float by unnoticed...

Not Lame

All this talk of atomic fussion, fission, atomic weight and whatnot begs the question of what the outcome would be if the BOFH and PFY got two Paris Hiltons and banged them together ?

http://www.jimbastard.com/Jim_pwns_a_womans_cell_phone_on_the_train.html

Best Feed Ever: http://feed.theregister.co.uk/atom?q=bofh

"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...

Damn, and I though I was nerdy.

You all need to chill out and just appreciate the storyline.

Now, While you are pondering that, Wheres my CattleProd....

<BRZZZZT>

OoPS WroNG End

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.

nice! ;)

cheers

The best explosive force is not as many believe the reaction of matter and anti-matter it is that of a 7y.o. with a half a can of red bull and a fairy floss coursing through his veins