E=mc^2 and is it possible E/c^2=m

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    E=mc^2
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Discussion Overview

The discussion revolves around Einstein's equation E=mc², exploring its implications regarding the conversion of energy and mass, and the concepts of rest and relativistic mass. Participants seek to clarify the meaning of the equation and its application in different contexts, including nuclear reactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants seek a simple explanation of E=mc² and question whether E/c² can equal m, referencing the conservation of mass.
  • One participant asserts that the statement about mass conservation is not true in relativity, emphasizing that total mass and energy are conserved.
  • Another participant highlights confusion between rest mass and relativistic mass, suggesting that discussions often pertain to relativistic mass.
  • Several participants reference external sources, like Wikipedia, to explain that E=mc² relates the energy equivalent of rest mass, noting the significant energy produced from small amounts of mass in nuclear reactions.
  • One participant points out that the equation can be interpreted differently depending on whether one is considering rest mass or relativistic mass.
  • There is a discussion about the conversion of energy into mass and vice versa, with some participants indicating that the answer varies based on the notion of mass used.
  • A participant questions the correctness of the original question, suggesting it should focus on the conversion of matter into energy instead.
  • Another participant raises a query about the differences in energy release between fission and fusion, linking it to binding energy and relativistic effects in high-energy particle interactions.

Areas of Agreement / Disagreement

Participants express varying interpretations of mass and energy conversion, with no consensus on the implications of E=mc². The discussion includes multiple competing views regarding the definitions and applications of mass in different contexts.

Contextual Notes

Participants note the importance of distinguishing between rest mass and relativistic mass, which affects the interpretation of energy-mass conversion. There are unresolved questions about the specifics of energy release in nuclear processes and the role of relativistic effects.

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can anyone explain in simple terms Einstein's equation E=mc^2 and is it possible E/c^2=m, because it is said mass can neither be created nor destroyed!
 
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arora-dhan said:
can anyone explain in simple terms Einstein's equation E=mc^2 and is it possible E/c^2=m, because it is said mass can neither be created nor destroyed!

That last statement is not true in relativity. It is total mass and energy that is conserved.
 


Every time people get confused by the difference between rest(invariant) and relativistic(conserved) mass.

When people come here after reading E=mc^2 they are definitely talking about the relativistic mass!
 


Also,wikipedia has a long winded explanation at
http://en.wikipedia.org/wiki/Mass_energy_equation

In brief, Einstein's equation relates the amount of equivalent energy in a rest mass.
A small amount of mass,m, produces a lot of energy, E, because the constant c is really,really big. for example,
E (in joules) = m (in kilograms) multiplied by (299,792,458 m/s)^2.

So for example, less than 1% of two pounds of uranium produced the atomic bomb blast (energy) at Hiroshima. (The other 99% was waste radioactive material.) And when the fission is controlled as in a nuclear power plant by slowing the cascading neutrons, a lot of power (energy) can be extracted over a longer period of time to produce useful electricity and steam (two forms of energy).(And there is still a lot of radioactive waste.)
 


Naty1 said:
Also,wikipedia has a long winded explanation at
http://en.wikipedia.org/wiki/Mass_energy_equation

In brief, Einstein's equation relates the amount of equivalent energy in a rest mass.

The same is applicable to the relativistic mass:

Wiki said:
E = mc^2 either means E = M0c^2 for an object at rest, or E = Mrel c^2 when the object is moving.
 


Post #6 is entirely correct...
I was keeping it SIMPLE...
The energy E can be considered as ALL forms of energy, heat, liner and angular momentum, kinetic and potential, gravitational, etc, as well as the component from rest mass...

If the mc2 equation is written as moc2 then one knows its rest mass for sure...but someone asking the question posted here is unlikely to make that distinction...
 


Yes, but how would your reply the question beginners ask many times:

E=mc^2, so energy can be convertedinto mass and vice versa?
Answer depends on what notion of mass do you use.
 


Dmitry67 said:
E=mc^2, so energy can be convertedinto mass and vice versa?
Answer depends on what notion of mass do you use.

what do you mean when you say "notion of mass"??
 
  • #10


I mean, answer is different for the rest and relatiistic mass.
 
  • #11


The question itself is incorrect. It should be "Can matter be converted into energy".
 
  • #12


I mean, answer is different for the rest and relatiistic mass.

How different is the answer for fission and fusion? anybody know?? Seems like it should be small...energy released is related basically to binding energy of the nucleus, right?

With high energy particles, as in acclerators, I can see momentum could be significant...relativistic considerations become significant...
 
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