Chapter 23, Problem 23.47P

A point charge q₁ = 4.00 nC is placed at the origin, and a second point charge q₂ = 3.00 nC is placed on the .x-ax is at x = +20.0 cm. A third point charge q₃ = 2.00 nC is to be placed on the x-axis between q₁ and q₂. (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 q₃ is placed at x = +10.0cm? (b) Where should q₃ be placed to make the potential energy of the system equal to zero?