particle 1 of charge q1 = +1.2 µC and particle 2 of charge q2 = -2.5 µC, are held at separation L = 14 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...