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Author Topic: Accord to E=mc sq, does a lb of ban have the same energy as a lb of plutonium?  (Read 3212 times)

Offline Joe L. Ogan

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According to E=MC squared, Does a pound of bananas have the same energy as a pound of plutonium?  If it does, why didn't they use bananas instead of plutonium.  Joe L. Ogan


 

Offline RD

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Nanas are not fissile.
« Last Edit: 12/11/2009 22:29:07 by RD »
 

Offline Joe L. Ogan

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E=MCsquared does not say anything about fizzle.
 

Offline JP

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Pounds is weight, not mass, but if they're at rest at the same place on the earth, then they would have the same mass, and since they're not moving in your reference frame, then you can use E=mc2 (momentum = 0).  Therefore, yes, they have the same energy in that reference frame. 

A lot of that energy is locked up in nuclear forces within the atoms that make up the plutonium or the bananas.  What RD was getting as is that plutonium is fissile, which means that nature has provided us with a relatively easy way of releasing that stored nuclear energy.  In the case of bananas, their atoms are much more stable, so it's harder to get at that energy.  A much smaller amount of energy is locked up in the chemical bonds between the various banana molecules.  You can get some of that out by simply burning the banana, but its a lot less than the nuclear energy.
 

Offline Joe L. Ogan

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Okay.  I understand your explanation.  But that sort of limits the Formula of E=MC squared does it not?  In other words some things are more equal than others.  Thanks for your reply.  Joe
 

Offline RD

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E=MCsquared does not say anything about fizzle.

You asked "why didn't they use bananas instead of plutonium".
The answer is because plutonium is fissile bananas are not.

If could fuse the atomic nuclei in the banana into larger atomic nuclei it would release* energy according to mc2.
The larger atomic nucleus would be slightly less massive than the sum of its parts and this mass difference would be released as energy (mc2).

[* provided the resultant nucleus was smaller than iron]

Fission of large unstable (radioactive) nuclei requires less energy than fusion of smaller nuclei.

[Nuclear fusion is what goes on in the Sun, so is quite difficult to recreate on Earth]
« Last Edit: 13/11/2009 01:08:15 by RD »
 

Offline JP

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Okay.  I understand your explanation.  But that sort of limits the Formula of E=MC squared does it not?  In other words some things are more equal than others.  Thanks for your reply.  Joe

If you're asking if E=mc2 tells you how much energy you can easily get from a given object, like a bunch of bananas or a handful of plutonium, then it's not a great predictor.  Even in a nuclear bomb, only a tiny amount of the mass is turned into energy (it's just that c is a huge number, so even a tiny amount of mass makes a huge explosion).

The real importance of the equation is that its a part of the larger theory of special relativity, which explains a lot of strange effects that happen when you start to move really fast (near the speed of light).
 

Offline Geezer

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Coincidentally, in one of the "Back To The Future" movies, Doc was able to refuel the DeLorean by popping a banana skin into the "Mr Fusion" reactor he had retrofitted to the car during one of his trips into the future.

I admit this information is of absolutely no scientific value, although it does help me remember the difference between fission and fusion.  ;D
 

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