Problem 4: A point charge of /2 pC is placed at the origin (x =0) of a coordinate system, and another charge of -2.J. p.C is placed placed on the r-axis at 12 = 0.22 m. Part (a) Where on the x-axis can a third charge be placed in meters so that the net force on it is zero?Part (b) What if both charges are positive; that is, what if the second charge is 2.3 uC