Essentially, each journey of the ball from floor to wall to floor, assumed to take place in the same vertical plane, comprises four events: (i) after launch from the floor the ball pursues a parabolic trajectory until it hits the wall, (ii) the rebound from the wall, (iii) the parabolic trajectory of the return journey to the floor and (iv) the impact with the floor which provides the launch data for the next excursion of the ball. The result of this analysis is the derivation of a non-linear mapping which relates the floor launch data (linear and angular velocity components of the ball and distance from the wall) to the same parameters after the next bounce on the floor.
In Section 3 some numerical trajectories of the non-linear mapping are computed and examples given of motions with various numbers of floor to wall bounces. Also illustrated are the parameter spaces of initial conditions required to produce various numbers of bounces off the wall. In Section 4 a scaling invariance is introduced which rewrites the non-linear map of Section 2 in terms of suitable canonical coordinates. This results in a three- dimensional non-linear map, a reduction in dimension by one from the original system.
Section 5 presents some numerical results for the regions of initial conditions which will result in a given number of bounces against the wall in the canonical variables, analogous to those of Section 3 for the original variables. The next two sections of the work analyse these numerical results in some detail, focussing on the behaviour of the mapping on two planes which comprise boundaries of the region of interest. The paper concludes by proposing a number of further questions related to the problem.
Before continuing to our analysis of the problem we have just described, we note that there are limitations to the model of the bounce of the superball that we use. It is recognised that the