The Magnitude of the Force That One Line Charge Exerts On The Other

[Tachyon]

Hello,

I've been reviewing some general physics and came across a

problem which has stumped me. If there is anyone out ther who can

point me in the right direction, that would be greatly appreciated. The

problem is the following:


Two thin rods of length L lie along the x-axis, one between x = a/2 and
x=a/2 + L, and the other between x = -a/2 and x = -a/2 - L. Each rod has a positive charge Q distributed uniformly along the length. Show that the magnitude of the force that one rod exerts on the other is

F = (Q^2/4*pi*epsilon(0)*L^2)*ln[(a + L)^2/a(a + 2L)]

 

[daniel_i_l]

I think that you just find the forcee as a function of the x position of the rod on the right and integrate from a/2 to L.