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ngkamsengpeter
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Homework Statement
Identical thin rods of length (2a) carry equal charges +Q uniformly distributed along their lengths.
The rods lie on (along) the x-axis with their *centers* separated by a distance b > 2a.
(Left rod from x=-a to x=a, right rod from x=b-a to x=b+a)
Show that the magnitude of the force exerted by the left rod on the right one is
[tex]F = k_e\frac{Q^2}{4a^2} \ln \frac{b^2}{b^2-4a^2}[/tex]
Homework Equations
The Attempt at a Solution
I think i should find the electric field at a point and then integrate it over the length of the rod to find the force But i even can't find the electric field . I see this question in the archieve but i just don't understand .
I know that we first find the E by integrating -a to a .After that we find the force by integrating from b-a to b+a right ? But the answer is integrating both from -a to a . Why not from b-a to b+a for the second times integration ?
Can someone help me to solve the questions?
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