[SOLVED] finding equilibrum point between two charges this is pure physics;ain't no theory development;so don't move me around. assume you have two charges q1 and q2 on distance R.the problem i'll solve here is how to find the equilibrum point between those charges. to do that you have to introduce new charge q3 in the system and place it somewhere between the first two on the conecting line.assume that distance between q1 and q3 is x then: F13x^2=-kq1q3 and F23(R-x)^2=-kq2q3 but it also has to be F13=-F23 this system of three equations gives the following: -x^2q2=(R-x)^2q1 the solution for x is: x1=(q1+sqrt(-q1q2))R/(q2+q1) x2=(q1-sqrt(-q1q2))R/(q2+q1) i wonder why if the charges are same by sing then x is some imaginary num and why if it is q1=-q2 then x is infinite/undefined point? am gratefull for your answers!!