1. The problem statement, all variables and given/known data Supopose you have two infinite straight line charges lambda, a distance apart , moving at a constant speed v. How great would v have to be in order for the magnetic attraction to balance the electrical repulsion ? Work out the actual number... Is this a reasonable sort of speed. 2. Relevant equations 3. The attempt at a solution F_mag= I (dl x B)=(lambda*v)(lambda*v)*dl/(2*pi*d) F_elec=(q_1*q_2/r^2)*(1/4*pi*epilison_0) Since the problem says that the magnetic attraction balances out the electrical repulsion, does that mean F_mag = F_elec?