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3 Point Charge Coulomb's Law problem

  1. Feb 5, 2009 #1
    1. The problem statement, all variables and given/known data

    3 Point charges are fixed in place in a right triangle. What is the electric force on the +1.0 nanoC charge due to the other two charges?

    Basically you have 3 charges in a right angle as decribed, lets call them A, B, and C. In the upper left you have A, +0.8 nanoC. 8cm directly below is B, -0.6 nanoC. To the right of B at unkown distance is C, +1.0 nanoC. the distance AC is given as 10 cm.

    So what is the electric force on charge C?

    2. Relevant equations

    I know I need Coulomb's Law. FE=k[tex]\bullet[/tex]q1[tex]\bullet[/tex]q2/d2

    3. The attempt at a solution

    so first i convert all charges from nanoC to C to make things easier so the charges are:

    A= 8e-7

    then i use pathagreom's theorum to find the distance BC, which is 0.06m.

    Then I draw all the Force components on point C.

    First I solve for FB using Coulomb's Law and get 1.5N in the -x direction.

    This seems to fine. I get stuck when trying to get the forces between point A and C...

    I can get the angles... sin-1(0.06/0.1)= 37 degrees.

    but i honestly have no clue what to do next, and have been scouring resources on the net for a solution and finally ended up here, still with no answer... please help!
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 5, 2009 #2
    hey thanks for everyone who looked at my question. i finally figured out the answer though! the net electric force on C should be 1.2 N at 28 degrees from the negative x axis
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