Charge q1 = +3.60 nC is on the x-axis at x = 0 and an unknown charge q2 is on the x-axis at x = -4.00 cm. The total electric force
that q1 and q2 exert on a third charge q3 = +2.00 nC on the x-axis at
x = 4.00 cm is in the +x-direction and has magnitude 54.0 μN. Find (a) the
magnitude and direction of the force that q1 exerts on q3, (b) the magnitude
and direction of the force that q2 exerts on q3, and (c) the charge q2.