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Homework Help: Find the force acting on the charge at the origin

  1. Jul 10, 2010 #1
    1. The problem statement, all variables and given/known data
    Three charges are fixed in the x-y plane as follows: 1.6nC at the origin (0, 0); 2.6nC at (0.55 , 0); –2.1 nC at (0, 1.15 ).

    Find the force acting on the charge at the origin.
    Express your answers using two significant figures. Enter the x and y components of the force separated by a comma.

    2. Relevant equations
    F=kQQ/r^2


    3. The attempt at a solution
    Fx=(2.6E-9*1.6E-9*9E-9)/1.15^2=1.24*10^-25N
    Fy=(2.1E-9*1.6E-9*9E-9)/0.55^2=2.29*10^-26N
    This is wrong but i cant see why??
     
  2. jcsd
  3. Jul 10, 2010 #2

    rl.bhat

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    Homework Helper

    For Fx r is 0.55 m not 1.15 m. And k = 9*10^9
     
  4. Jul 11, 2010 #3
    thanks rl.bhat I have the right answers now. I just dont know which one would be negative, I am thinking Fy??? thanks
     
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