This references a specific problem in my Physics class in relations to electrical potential and electrical fields, but I kind of want a more general answer in terms of physics. So obviously, I know that distance is always positive. However, when I was given a problem to solve, there were 3 different charges with their own respective charges. This is not really a homework problem since I already know how to use the given information to solve for electric potential and electric field. Long story short, when I was plugging in the numbers, apparently I got the answer wrong for calculating the total charge at a single point because I used a negative number for distance. My physics teacher told me that distance is always positive, but by my mathematical analysis, it looked almost like it was -x distance from the origin (or in this case, the point). Well, this is a problem that I really need to know, especially if electrical engineering is going to involve a lot of physics like this. I know distance in theory is positive. However, if I was given a formula and the formula had the letter "r" or "R" in it, does that mean that it will always denote a positive number since it is a distance? I am sorry if this is a dumb question, but like I said, I want to make sure I am 100% prepared for engineering school and the only way I can do that is by improving my physics. I am good with the math, but I just want to sharpen that physics a little bit. Thank you!