Calculating Net Force Between Two Dipoles

In summary, the conversation discusses the calculation of the net force between two identical dipoles with charge q and separation a, a distance x apart. By considering forces between pairs of charges in the dipoles, the net force is found to have magnitude 6kp^2/x^4 in the limit a<<x, where p=qa is the dipole moment. The equation for the force between two charges is E=2kp/x^3, and in this case, Coulomb's law can be used with q as the charge to calculate the force.
  • #1
kjintonic
11
0

Homework Statement


Two identical dipoles, each of charge q and separation 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.


Homework Equations


E=2kp/x^3


The Attempt at a Solution


I have no idea where to start T^T
 
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  • #2
They say to calculate forces between pairs of individual charges.

Which equation gives the force between two charges?
 
  • #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:
  • #4
K now I understand that you have to use coulomb's law but how on Earth do i find q of one dipole?
 
  • #5
Yes, use Coulomb's law.

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

What is a dipole?

A dipole is a pair of equal and opposite charges separated by a distance. This creates a net charge, or dipole moment, with a positive end and a negative end.

What is the net force between two dipoles?

The net force between two dipoles is the sum of all the individual forces between each pair of opposite charges. This can be calculated using Coulomb's law and taking into account the distance and orientation of the dipoles.

How is the net force affected by the distance between two dipoles?

The net force between two dipoles is inversely proportional to the square of the distance between them. This means that as the distance increases, the force decreases.

Can the net force between two dipoles be zero?

Yes, the net force between two dipoles can be zero if the dipoles are oriented in such a way that their forces cancel each other out. This can occur when the dipoles are aligned in opposite directions or when they are perpendicular to each other.

How does the orientation of dipoles affect the net force between them?

The orientation of dipoles can greatly affect the net force between them. When the dipoles are aligned in the same direction, the force is attractive. However, when they are aligned in opposite directions, the force is repulsive. Additionally, the force is strongest when the dipoles are aligned parallel to each other.

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