Electrostatic Forcce :( 1. The problem statement, all variables and given/known data In Fig. 21-26, particle 1 of charge q1 = +1.4 µC and particle 2 of charge q2 = -4.2 µC, are held at separation L = 12 cm on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the (a) x and (b) y coordinates of particle 3? 2. Relevant equations F = (Q1 * Q2)K/ r^2 3. The attempt at a solution At first i thought i could go about this problem setting the particle to the left of the two i figured that the charge on Q2 > Q1 so its pull would be compensated by Q1's push (i made my particle three positive) then i set F31 = F32 so that their forces would balance out to 0 that would make my y placemnt 0 as well but now...im stuck i did som canceling until i finally go to this: (r^2) Q2 ------------ = --------- (0.12 +r)^2 Q1 or (r^2) / (0.12 +r)^2 = Q2/ Q1 and i don't know wehre to go from there so... is there a way out or was i supposed to envision particle three somewhere else??