I am trying to calculate the final velocities of two equal mass 2-dimensional circles after an elastic collision. I have tried to figure it out using formulas I know from high school physics, but nothing seems to work. My known variables are: - initial x and y velocities for each circle - x and y distances between the centres of the circles at the time of the collision The variables I would like to solve for are: - final x and y velocities for each circle Here are diagrams showing all the variables: [![variable diagrams][1]][1] [1]: https://i.sstatic.net/pHezv.png