A point charge `q_1 = 4.00 nC` is placed at the origin, and a second point charge `q_2 = -3.00 nC`, placed on the x-axis at x = + 20.0 cm. A third point charge `q_3 = 2.00 nC` is placed on the X-axis between `q_1, and q_2`. (Take as zero the potential energy of the three charges when they are infinitely far apart).
(a) What is the potential energy of the system of the three charges if `q_3` is placed at x= + 10.0 cm?
(b) Where should `q_3` be placed to make the potential energy of the system equal to zero?