Hi! I'm trying to understand the concept of the center of mass. I know the center of mass is the point within the object where it could be considered that the entire mass of the object lies, thus forces are going through this center, but how is it possible that the center of mass could move before a collision? Additionally, if it does do that, what happens to it after a collision? Does it go back to its original point? How does all that work out? Thanks in advance!