Hello Does anyone know how to model a ball (sphere) with mass spinning with an initial angular velocity that gets dropped on the floor with a coefficient of friction? And find the final angular velocity? I tried solving the problem but somehow I got a singularity. The idea I used was the work from friction equals the change in the kinetic energy (rotational and translational) but even after I reworked I got a singularity so i must be doing something wrong. Thanks for your help.