1. The problem statement, all variables and given/known data Two particles with positive charges q_1 and q_2 are separated by a distance s. Along the line connecting the two charges, at what distance from the charge q_1 is the total electric field from the two charges zero? (Express your answer in terms of some or all of the variables s, q_1, q_2 and K =1/(4*pi*[itex]\epsilon[/itex]. If your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.) 2. Relevant equations E = K*(q/(d)^2) E_net = E1 + E2 3. The attempt at a solution Since both the charges are positive, my E_net = E1 - E2. So I can solve this by finding where E1 and E2 are equal. Setting the two equations equal I get K(q_1/s^2) = K(q_2/s^2) Since I'm just concerned with finding the distance from q_1 to the point where the e-field is zero, wouldn't my equation be: s_1 = (q_1 - (q_2/(s_2)^2) Since none of the variables are defined, I'm having a hard time figuring out how to choose my 's' (distance). Wouldn't the distance ('s') depend on the magnitude of the charge on q_1 and q_2? How can I show that algebraically without somehow renaming the distance variable something other than 's'?