1. The problem statement, all variables and given/known data A proton starts at rest and travels through a potential difference of 8000V. What's it's final speed. 2. Relevant equations ΔEe+ΔEk=0 ΔEk=-ΔEe Ee=qV 3. The attempt at a solution I know how to find the correct magnitude, but I am getting the wrong sign. Ek=-ΔEe 1/2mv^2=-qΔV v=root [-(2qΔV)/m] Note mass of proton=1.67 x 10^-27 kg v=root[-2(1.6.x10^-19)(8000))/1.67 x 10^-27] I get an error because obviously there isnt a root for a negative value of [-2(1.6.x10^-19)(8000))/1.67 x 10^-27]. I want to know where I am going wrong in terms of positive/negative.