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Math Help - mass and energy query

  1. #1
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    mass and energy query

    According to Einstein’s equation, what mass is equivalent to an energy of
    6.7 × 10–14 J? You should use a value for c of 3.0 × 108 m s–1
    and can you please give your answer in kilograms, in scientific notation and to two significant figures.

    thx trigger
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  2. #2
    Rhymes with Orange Chris L T521's Avatar
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    Quote Originally Posted by trigger View Post
    According to Einstein’s equation, what mass is equivalent to an energy of
    6.7 × 10–14 J? You should use a value for c of 3.0 × 108 m s–1
    and can you please give your answer in kilograms, in scientific notation and to two significant figures.

    thx trigger
    Since E=mc^2, and you want mass....we see that m=\frac{E}{c^2}

    You are given E and c...its just "plug n' chug" from here...
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  3. #3
    o_O
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    What exactly are you having trouble with?

    E = mc^2 \ \Leftrightarrow \ m = \frac{E}{c^2}

    You have the energy (note that a joule can also be expressed in SI units: kg \cdot m^2 \cdot s^{-2} ) and you have the speed of light.

    Just a matter of plugging it in.
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