My physics world was stunned today. I've been studying classical physics for several years now and just came across the concept of "Jerk"--the derivative of acceleration or the third derivative of position. I initially thought it was a joke or some some "fringe force" concept, perhaps something like centrifugal force. But then I did some research and found out the maths of these 3rd derivatives is routinely used by engineers in designing cars, rollercoasters, etc. I am blown away, I always thought that all we needed to understand classical mechanics was two time derivatives of position, that's it. Can someone explain to me why I've never seen this in full semester and year-long courses in classical mechanics?