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Net force between two dipoles

  1. Sep 7, 2008 #1
    1. The problem statement, all variables and given/known data
    Two identical dipoles, each of charge q and seperation a, are a distance x apart, as shown in Fig. By considering forces between pairs of charges in the different dipoles, calculate the net force between the dipoles. Show that, in the limit a<<x, the force has magnitude
    6kp^2/x^4, where p=qa is the dipole moment.


    2. Relevant equations
    E=2kp/x^3


    3. The attempt at a solution
    I have no idea where to start T^T
     
  2. jcsd
  3. Sep 7, 2008 #2

    Redbelly98

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    They say to calculate forces between pairs of individual charges.

    Which equation gives the force between two charges?
     
  4. Sep 7, 2008 #3
    I really don't know... I am a 11th grader and I'm asked to do university stuff;;

    oops i forgot the diagram

    ----- (- +) ---------------------------------(- +)----
    --------a--------------------x-----------------a

    EDIT: You mean kq1q2/r^2 ??
     
    Last edited: Sep 7, 2008
  5. Sep 7, 2008 #4
    K now I understand that you have to use coulomb's law but how on earth do i find q of one dipole???
     
  6. Sep 7, 2008 #5

    Redbelly98

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    Yes, use Coulomb's law.

    Just leave the charge as q and work through the algebra.
     
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