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Urgent Help : Einsteins derivation of e=mc^2

  1. Jan 4, 2005 #1

    This has probably been asked and answered a million times before so sorry but here goes. I urgently need help with a Maths University project about the A-Bomb which will include a chapter on Special Relativity and e=mc^2. I have read loads of books but they treat special relativity from a modern view point whereas I need to know how Einstein "figured out" e=mc^2 as it's a projcent on the impact and development of maths. Can anyone explaine how Einstein derived e=mc^2 or recommend and books/websites. Also, does anyone have any useful mathematical info on the development of the A-Bomb that might help?

    Thanks :smile:
  2. jcsd
  3. Jan 4, 2005 #2

    Doc Al

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    Staff: Mentor

  4. Jan 5, 2005 #3


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    Where did E^2=m^2c^4+p^2^2 come from?

    And why can't users view their own "warnings?"
  5. Jan 5, 2005 #4


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    Actually, it's

    [tex]E^2 = m_0^2 c^4 + p^2 c^2[/tex]

    and it is the same as [tex]E = mc^2[/tex] which uses the "relativisitc mass" whereas the previous expression uses the "proper mass."
  6. Jan 8, 2005 #5


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    Ummm, which one is rest mass and which one is not? Rest mass is proper mass? Right?
  7. Jan 8, 2005 #6


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    ...and you can derive it by starting with the relativistic equations for energy and momentum:

    [tex]E=\frac {m_0 c^2} { \sqrt {1 - \frac {v^2} {c^2}}}[/tex]

    [tex]p=\frac {m_0 v} { \sqrt {1 - \frac {v^2} {c^2}}}[/tex]

    and combining them so as to eliminate v.

    Right. It's also known as "invariant mass".
    Last edited: Jan 8, 2005
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