1. The problem statement, all variables and given/known data A proton, initially at rest, is accelerated through an electric potential difference of 500V. What is the speed of the proton? 2. Relevant equations V=k(q/r) Solving for r: r=k(q/v) v=d/t known charge of a proton: 1.6E-19C known value of k: 9E9Nm^2/C2 3. The attempt at a solution I tried solving for r to get a distance. r= (9E9Nm^2/C2)(1.6E-19C)/ 500V r= 2.88E-12m v=d/t v= (2.88E-12m)/1 s v= 2.88E-12 m/s Our professor gave the answer as 3.1E5 m/s, but I cannot get to this answer. Any help would be greatly appreciated!!