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Homework Help: What is the new separation between the charges?

  1. Jul 11, 2008 #1
    1. The problem statement, all variables and given/known data


    Two positive point charges are held in place, 0.86 m apart. They are then moved so that their electric potential energy doubles. What is the new separation between the charges?
    2. Relevant equations

    kq/r

    3. The attempt at a solution
    had PEb=KQaQb/d=2EPEa, then did KQaQb/d=2(KQaQb/.86. but cannot figure out how to solve it further
     
  2. jcsd
  3. Jul 11, 2008 #2

    Doc Al

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    Staff: Mentor

    This is good. Simply and solve for d. Start by canceling everything that can be canceled from both sides of the equation.
     
  4. Jul 11, 2008 #3
    both sides of the equation had KQaQb, i cancelled the part out on both sides, leaving, 1/d=2(1/.86). then 1=2.32d. d=.43?
     
  5. Jul 11, 2008 #4

    Doc Al

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    Staff: Mentor

    Looks good to me.
     
  6. Jul 11, 2008 #5
    awesome, thanks
     
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