1. The problem statement, all variables and given/known data at what speed does the expression for relativistic kinetic energy vary from the non-relativistic expression by 5%? 2. Relevant equations Relativistic kinetic energy K=(gamma-1)mc^2 Non-relativistic kinetic energy K=0.5mv^2 3. The attempt at a solution I'm not sure how to attempt this! Should I be finding the difference? ie K(relativistic)-K(non-relativistic)=0.05??