1. The problem statement, all variables and given/known data A very long, thin straight line of charge has a constant charge density of 2.0pC/cm. An electron is initially 1.0cm from the line and moving away with a speed of 1000km/s. How far does the electron go before it comes back? 2. Relevant equations ΔU = ΔV*q ΔKE + ΔU = 0 ΔV = -2Kλln(rb/ra) W = 2Kλqln(rb/ra) W = -ΔU 3. The attempt at a solution first off: 2.0pC/cm = 200pC/m 1000km/s = 1x10^6m/s KEa + Ua = KEb + Ub 1/2mv^2 + Ua = 0 + Ub 1/2mv^2 = Ub-Ua 1/2 * (9.1x10^-31)*(1x10^6)^2 = -ΔU 4.55x10^-19 = -ΔU W = -ΔU 4.55x10^-19 = 2Kλqln(rb/ra) 4.55x10^-19 = 2K(200x10^-4)(1.6x10^-19)ln(rb/.01) 7.899x10^-9 = ln(rb) - ln.01 ln(rb) = 4.605 rb = 100m Well, that is the process that I followed, and I feel like I did ok, except that the majority of the rest of my class got different answers. They all got .66m, which seems more realistic, 100m just seems too far. I have another question that again, I seem to get a different value than everyone else. I think I may be screwing up the conservation part in the beginning, but I have no idea where I'm going wrong. I asked my teacher, and he said to use ΔU = ΔV*q, but other than considering ΔV = -2Kλln(rb/ra) & W = 2Kλqln(rb/ra), I don't know where I would use it. Any help would be greatly appreciated.