Thin Rod + Poncual Charge.... Find Vb-Va 1. The problem statement, all variables and given/known data A thin "rod" of 10 m is located between (0m,4m) and (0m,14m). Its linear density is 50*10^-9C/m. Also, there is a ponctal charge of Q=10*10^-9 located at (-1m,0m). Given 2 points: A at (0m,-5m) B at (0m,0m) Find Vb-Va. 2. Relevant equations E=k|Q|/r^2 E*d=V some integrals... 3. The attempt at a solution Okay, this seems like a tricky one, does it not? I know I could use Vb-Va = Integral of : E*s, possibly with s=5 But then, I would have a Vb-Va for the rod, would I have to also calculate the Vb-Va due to the poncyal charge and then sum these 2? This is what I would have done during an exam, though I'm really not sure it'd be good, would it? Thanks for any help you can provide... belive me, I,ve tried it a couple of times before posting here.