Hello!

I want to make a model with an inner moving circle touching a non-moving, stiff outer circle. 2 differential equations describe the movement of the inner circle, i already have modelled thisand i have the x and y coordinates of the most "exposed point" which will touch the outer circle, as output variables (i could also add the derivatives as output). When the 2 circles touch, i want to "tell" the differential equation model the 2 new derivatives for x and y...