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Homework Help: Point charge attractioning a positive charge from infinity to 30cm

  1. Sep 17, 2008 #1
    1. The problem statement, all variables and given/known data

    A point charge of 2.0 10-9 C is located at the origin. How much work is required to bring a positive charge of 4.0 10-9 C from infinity to the location x = 30.0 cm?

    and it requests the answer in J

    2. Relevant equations


    DeltaV = Ke q1/d

    where delta v is potential difference, W is work, q2 and q1 are the charges, Ke is coulombs constant, and d is distance

    3. The attempt at a solution

    I plugged in all of the variables using 4.0 *10 ^ -9 as my q1 and 2.0*10^-9 as my q2 and that was wrong so i switched them.. again wrong..
  2. jcsd
  3. Sep 17, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Switching q1 and q2 won't change anything. Show your final expression for the work done and the numbers you plugged in. Is it positive or negative?
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