1. The problem statement, all variables and given/known data A charge of –4.00 µC is fixed in place. From a horizontal distance of 55.0 cm, a particle of mass 2.50 × 10–3 kg and charge –3.00 µC is fired with an initial speed of 15.0 m/s directly toward the fixed charge. How far does the particle travel before it stops and begins to return back? 2. Relevant equations KE = 1/2 mv^2 Pba = -W = -qEd F = kQ1Q2/r^2 3. The attempt at a solution 1) Found the Kinetic energy of the moving particle : KE = 1/2mv^2 = 1/2 (2.5x10^-3)(15)^2 = 0.281 J 2) Set the value I found for KE to PE and used the Potential Energy eqn: PE = -qEd Since E = kQ/d^2 PE = -qd(kQ/d^2) Therefore: d = -qkQ/PE d = 0.38 m I'm not sure if I did that right. But the answer I came up with looks like it could work. Any help would be appreciated!