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Homework Help: Finding the distance between two charges

  1. Sep 9, 2015 #1
    1. The problem statement, all variables and given/known data
    The potential energy of a system of two charges (q1 = 5.0 µC and q2 = 3.3 µC) is 0.37 J. What is the distance between the charges?

    2. Relevant equations
    U=(kq_0q)/r --> r=U/(kq_0q)


    q1 = 5.0 µC
    q2 = 3.3 µC

    3. The attempt at a solution

    So I was going to use equation 2 but I have two charges involved and that one only asks for q_0.
    Do I calculate the change of the charge and use that for q_0?
  2. jcsd
  3. Sep 9, 2015 #2
    V is potential.
    U is potential energy.
  4. Sep 9, 2015 #3
    Wow, that cleared up a lot so,

    r= 0.37J/((8.99e9)(5e-6)(3.3e-6)) ?
  5. Sep 9, 2015 #4
    Try solving for r again,you've made a mistake.
  6. Sep 9, 2015 #5
    Was it the micro?
  7. Sep 9, 2015 #6
    No.And it's the correct equation.The fraction is mot correct,though.
  8. Sep 9, 2015 #7
    Seeing it in this form might help you: ##U=\frac{q_1q_2}{r} ##
    So,does ##r=\frac{U}{q_1q_2} ##?
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