1. The problem statement, all variables and given/known data Here is the problem given. The answer is E. 2. Relevant equations No equations are given. Assumed use of standard equations for electric field and force involving electric field. 3. The attempt at a solution I tried using a few equations (E = F/q0), (F = mv^2), (E=(1/(4piEp0))(q/r^2)), and solving, but no luck. Could someone please give me guidance?