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Homework Help: Calculating coulombs with 3 charges

  1. Feb 26, 2009 #1
    1. A positive charge of 2.6 µC is pulled on by two negative charges. One, -2.0 µC, is 0.050 m to the north and the other, -4.0 µC, is 0.025 m to the south. What total force is exerted on the positive charge?

    north east south west?


    2. I'm using the equation Kq1q2/d^2 k=9E9 q=charge r=distance


    3. anyone that could help this would be great i tried calculating the force of 1 acting on 3 then 2 acting on 3 and 2 acting on 1 and added them but still no luck anyone that could show how to complete this 3 charge coulomb force would greatly be appreciated
     
  2. jcsd
  3. Feb 26, 2009 #2

    lanedance

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    work out the field without the +ve charge, ie the contribution form each -VE charge, be careful with direction then use F = Eq for tehforce on the negative charge

    note it only asks for the force on teh negative chareg due to the poistive charges
     
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