electron together 2 electrons are fired at speed v towards one another. Knowing that each electron has a charge of e an mass m, what is the minimum distance that the two electrons will reach after fired at one another? My book has a different answer than me so I have to check with you guys. I wrote, -dE = dEk -(E2 - E1) = (Ek2 - Ek1) - Ek2 is zero to for minimizing radius, and we assume E1 to be zero. E2 = Ek1 2ke^2/r =mv^2 2ke^2 / mv^2 = r Now in our book, they had this question with numbers, i derived this formula and plugged in my values and it didn't match the answer in the book.