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E=mc question

  1. Aug 23, 2012 #1
    c=speed of light

    i am not one of you. im a simple joe.
    energy =mater times the speed of light. Times the speed of light. ?
    energy=mater times (ℂ time ℂ) ? (aprox 36 trillion)

    Next question.
    If we know the formula, what are the measurements? are we talking pound of iron?
    or one atom of iron?
    are we talking one Wat or one mega-gigawatt's?
    How much mater are we talking about?
    Assuming one was to beam Capt Picard and he weighs 170 pounds.
    we need to know if the formula is per atom of pound of baldness.
    Please, KIS,IS keep it simple, im stupid.
  2. jcsd
  3. Aug 23, 2012 #2
    The two are equal.

    It doesn't matter. That's the point of this formula, we can apply it to a mass of any size.
  4. Aug 23, 2012 #3
    Ok. it does matter.
    if we are talking
    1 wat per pound.
    1gigawat per atom.
  5. Aug 23, 2012 #4


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    Consider it this way:

    E = energy in joules
    M = mass in kilograms
    C = speed of light in metres per second

    So if you had 1kg that would be:

    E = 1 * 2997924582

    Which is:

    8.98755E+16 Joules

    So 1 kg of mass represents 89.8Petajoules of energy (peta = 1*1015)

    FYI a watt is a joule per second. So 1 gigawatt would be 1 billion joules per second (giga = 1*10^9)
  6. Aug 23, 2012 #5


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    Staff: Mentor

    By comparison the US average electricity output is about 1.6 E+15 J/hr
  7. Aug 23, 2012 #6
    This is what I was looking for. thank you.
    on a side note.

    I thought ℂ= 186,k miles per sec.
  8. Aug 23, 2012 #7


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    C is the speed of light, it can be expressed in any unit of distance over any unit of time but for the same of e=mc2 if you're going to use SI units then use metres per second.
  9. Aug 23, 2012 #8
    Not that I can. but.
    at 175 pounds. or 79.37
    E=2,745,884,520,000 Joules needed to form
    M 79.37

    we are skipping the facts that it would have to be put together in a sequence to that of a DNA strand.

    thank you for helping me understand the formula. PF mentor.
  10. Aug 23, 2012 #9


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    I don't understand what you mean here. 175lb = ~79.37kg but that equates to 7.14e18J.
    This sentence makes no sense :confused:
    No worries but given this post I'm not sure you understand yet.
    Last edited: Aug 23, 2012
  11. Aug 23, 2012 #10

    Consider this:

    Body is standing still. Just chilling.

    Then this still body emits two identical photons of light, both at the same moment: one to the left, and one to the right.

    Photons are on their way now, away from body, carrying energy. Both photons are same, they are identical. They carry same amount of energy. So - body is still still.

    Photons carry energy away. So body must have lost this energy. Energy was taken from body and is now going away, photons carry it away. Thus, body lost some energy.

    But: what is this lost energy? Body is still. Body was still. What did body lose then?

    You can say body lost mass - what else is there body could lose?. Like, when You and Your friend are on a boat, on a river, and You both throw away two identical balls, at the same time, to the left and to the right. Balls have mass, right? So You and Your boat lost some mass -- mass of two balls. But: photons don't have rest mass! They just have energy and move at speed of light! So, body lost mass, which is actually energy moving with speed of light :smile:

    When all the numbers are put together one finds [itex]E = m c^2[/itex]. Two photons have energy [itex]E[/itex] both together, and body lost mass [itex]m[/itex]. Speed of light is [itex]c[/itex].

    Simple enough, right? I hope this helps a bit.

  12. Aug 23, 2012 #11
    175 is the weight in pounds. the converter says 79.3 Kg. took that times C times C and got 2,745,884,520,000.
    As the reply said that the unit is Kg for mass and Joules for E then it would take 2,745,884,520,000 joules of power to create that 175 pounds. but in transportation (beaming) you would still need to assemble the mass in the original form.

    All I really wanted was to know what measurements the E and M are.
  13. Aug 23, 2012 #12


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    You have to times the mass in kilograms by the speed of light squared. The gives you the energy. So;

    E = 79.3 * 2,745,884,520,000

    Also it's worth pointing out that star trek transportation is nothing more than fiction. If you magically converted the mass of a person to energy you wouldnt get a beam-me-up moment, you'd get a massive explosion.
  14. Aug 23, 2012 #13
    I am aware that trek beaming is fiction. but i did not know what the units was. be it per Kg or per atom.
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