Hi everybody, I am trying to find the resulting x and y velocities when two moving circles (particles) which are exactly the same and are in the same plane, collide. They are not (necessarily) hitting head on. I am trying to implement this in a 2d computer simulation. I have the x and y velocities and coordinates of the two particles, but I have not taken a physics class, and most formulas I can find online involve vectors-- I don't entirely understand vectors and can't figure out how vectors can be converted to and from x and y velocities. Is there a formula to find resulting x and y velocities given the original x and y velocities and the coordinates of the circles at the exact point when the circles meet? Thank you so much for your help. -yortzec EDIT: This post has been moved.