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Kinetic energy and momentum

  1. Nov 14, 2007 #1
    So I have a physics problem that has the normal equation KE=1/2mv^2 and KE=p^2/2m and i have no idea how they get the second equation is it a derivative or something with calculus? any helps greatly appreciated thanks in advance.
     
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  3. Nov 14, 2007 #2

    ZapperZ

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    p=mv.

    Use that in the first equation.

    Zz.
     
  4. Nov 14, 2007 #3
    Here is how it is derived:

    p=mv

    KE=(1/2)mv^2

    KE=(1/2)mv*v (mv=p)

    KE=(1/2)pv (v=p/m)

    KE=(1/2)p*(p/m)

    KE=(1/2)*(p^2/m)

    KE=p^2/2m


    Hope that helped.
     
  5. Nov 15, 2007 #4

    ZapperZ

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    We usually try to get the person to do or discover the answer for him/herself, rather than spoonfeeding the answer completely.

    Zz.
     
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