This may not be a challenge for some of you, but it is hard for me as I just got introduced to the topic, your help will be appreciated. It is about Electric Force. Coulomb's Law. 1. The problem statement, all variables and given/known data Charges of -1 micro coulomb and -4 microcoulomb are placed at opposite ends of a meter ruler. Where on the ruler could... (a) a free electron be placed and be in electrostatic equilibrium? (b) a free proton be placed and be in electrostatic equilibrium? 2. Relevant equations F=K(q1q2)/r2 F= Force (Newtons) Q= Coulombs charges R= distance between the charges K= botlzmann constant 3. The attempt at a solution I tried getting the answer by doing math without involving phyisics, like this: If 4 microcolombs is 100% then 1 microcoulomb might be 25% and I have a 1 meter long ruler, then the new coulomb would be placed 25% to the right from the force that has 1 microcoulomb. That would be 25 cms to the right from the -1 microcoulomb I reach this conclusion by math logic, but I believe it's wrong and my teacher told me it really is wrong, my method is ambiguous so.. I hope someone helps me get me the correct answer.