1. The problem statement, all variables and given/known data: Three parallel wires of length l each carry current i in the same direction. They’re positioned at the vertices of an equilateral triangle of side a, and oriented perpendicular to the triangle. Find an expression for the magnitude of the force on each wire. Express your answer in terms of the variables i, l, a, and appropriate constants. 2. Relevant equations: F = [(permittivity constant)(current 1)(current 2)(length)] / (2pi)(distance apart) This is the equation for the magnetic force between two wires 3. The attempt at a solution u is permittivity constant l is length d is distance between wires I started by trying to find the force on the middle wire: F on wire 2 = force on 2 from 1 + force on 2 from 3 = [ (u*i1*i2*l) / (2pi*d) ] + [ (u*i3*i2*l) / (2pi*d)] Since all three currents are the same: = [ (u*i^2*l) / (2pi*d) ] + [ (u*i^2*l) / (2pi*d) ] = 2(u*i^2*l) / (2pi*d) = (u*i^2*l) / (pi*d) On my equilateral triangle, I drew the three wires pointing directly upwards from the vertices of the triangle. Since the base of the triangle is a, the distance that wire 2 is from wires 1 and 3 is a/2: = (u*i^2*l) / (pi*(a/2)) = 2(u*i^2 *l) / (pi*a) This is the answer I have but I have made a mistake, I just don't know where.