1. The problem statement, all variables and given/known data Show that 1/2mγv^2 does not give the correct kinetic energy. 2. Relevant equations 1/2mγv^2 γ = 1/(sqrt(1-v^2/(c^2))) 3. The attempt at a solution Well, since the classical mechanics version of kinetic energy was the integral of momentum with respect to v, I felt I could simply explain that the v^2 in the denominator of γ must be integrated as well. However, the integration that I get from applying this to the equation is different than the actual equation for relativistic kinetic energy. I'm assuming the issue is when it comes to relativistic kinetic energy, you cannot integrate the relativistic momentum with respect to v and get the correct answer, but can someone tell me why and a better approach to showing why their equation of 1/2mγv^2 is invalid?