1. The problem statement, all variables and given/known data A rod of length L lies along the x axis with its left end at the origin. A total charge Q is distributed non-uniformly on the rod, so that ?=ax, where a is a positive constant. (a)Determine the constant a. (b) What is the potential due to this charged rod at a point along the positive x-axis, past the end of the rod? (c) A point charge +2Q is placed at 3L from the origin on the positive x-axis. What is the potential energy of this system? 2. Relevant equations dq=λds dV=(dq)/(4pi)(ε0)r dU=Vdq 3. The attempt at a solution I completed part a and got a=(2Q)/(l2) my attempt at part b: V=∫dV=∫(ax dx)/(4pi)(ε0)r From there my question is more what is the value of r? is it x? From there im sure i can figure out the rest.