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Kinetic energy of bullets

  1. Nov 14, 2009 #1
    1. The problem statement, all variables and given/known data

    two 3.5g bullets are fired with speeds of 42.4 m/s and the 2nd one with 69.6 m/s

    what is the kinetic energy of the first bullet?
    the second one?


    2. Relevant equations

    EK=(1/2)mv^2

    3. The attempt at a solution

    EK=(1/2)3.6*42.4^2 = 3235.968

    it is wrong.. why?
     
  2. jcsd
  3. Nov 14, 2009 #2

    mgb_phys

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  4. Nov 14, 2009 #3
    you have not converted the mass of the bullet from grams to kgrams

    0.50 x (3.5x10^-3) x 42.4^2 = 3.14J

    this is the answer i got
     
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