So, there is a sentence in my book, along with a graph, stating that "relativistic kinetic energy becomes infinite as v approaches c." But then in a concept problem, it says "A proton is accelerated from rest by a constant force that always points in the direction of the particle's motion. Compared to the amount of kinetic energy that the proton gains during the first meter of its travel, how much kinetic energy does it gain during one meter of travel while it's moving at 99% of the speed of light" The answer is the same, it says, because there is no change in kinetic energy since there is constant force. But I thought since the first statement above said that kinetic energy --> infinity as v -- c..... means that as v increases, KE increases, right? But that is not so in the problem. Could someone explain why this is so? Thanks!