The direction in which I see JFK's head moving makes no difference, because I am not an expert. But if you want to pursue this, perhaps you should start here: Kinetic Energy, Bullets and Collisions: A Maths Tutorial The quadratic dependence of kinetic energy on velocity has many implications. In this article, we talk about kinetic energy, bullets and collisions. https://www.futurelearn.com/info/courses/maths-linear-quadratic/0/steps/12123