1. The problem statement, all variables and given/known data http://puu.sh/bz0km/092f2d8781.png 2. Relevant equations h^2/2ma^2 3. The attempt at a solution I've found the uncertainty of the kinetic energy through many means, and I'm confident that it's .052MeV. The easiest method that gave me this answer was: using http://puu.sh/bz0Fm/f45f952a89.png ((1.05*10^-34)^2 / 2(6.64*10^-27)(10^-14)^2 ) / 1.6*10^-19 = .052MeV So I know that the kinetic energy has an uncertainty of .052MeV and that its typical energy is 5MeV, so wouldn't the answer just be 5MeV - .052MeV = 4.948MeV?