The ringing of Euler's disk (Q1860540)

The motion of disks on tables has the well-known feature that the associated acoustic signal increases in frequency as the motion tends toward its abrupt halt. Recently, a commercial toy, known as Euler's disk, was designed to maximize the time before this abrupt ending. In this paper, the authors present and simulate a rigid body model for Euler's disk. Based on the nature of the contact force between the disk and the table revealed by the simulations, they conjecture a new mechanism for the abrupt halt of the disk and increased acoustic frequency associated with the decline of the disk.