The physics of a controversial goal (collision theory teaching)

A study was carried out to investigate whether there are any conditions consistent with the laws of physics in which a hockey ball could strike a goal post, score a goal and return to the field of play without the intervention of a player. The analysis is within the compass of elementary undergraduate mechanics (and some sixth formers) and provides a good example of the application of the physics of collisions to a real-life macroscopic example.