Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook