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Homework Help: Coulomb's Law (Electricity and Magnetism) Question

  1. Jan 24, 2007 #1
    1. The problem statement, all variables and given/known data
    Five point charges on a straight line are seperated by a distance of 0.01 m. For what values of q2 and q4 would the net force on each of the other three charges be zero?


    q1= 2x10^-6 C
    q3= 1x10^-6 C
    q5= 2x10^-6 C

    2. Relevant equations

    Force = (q1q2K)/r²
    Where q are the charges, K is a constant (8.99x10^9) and r is the distance between the charges.
    The problem is solved using a free body diagram and a summation of forces.

    3. The attempt at a solution

    I have no idea as to how to approach this problem, I'm not looking for a full solution but for some advice. My main questions are; how do I deal with the forces and their directions? Then how can I use algebra to optain the values of q2 and q4?
  2. jcsd
  3. Jan 24, 2007 #2
    Sum up the forces for q1, q3, and q5. You shoud have 3 equations and 2 unknowns, because you know the distance each force acts over
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