I know about how to track relative motion by creating a point mass and use it to move a dynamic coordinate system.¹  I want to develop a conservation of angular motion lab and want to track the relative rotation of one object w.r.t. another.  More importantly I want to track the rotation of any moving object around it's center of mass.  

What I have tried so far:
As an example look at the NTNU videos involving 2D collisions. The c.o.m. of each object is clearly visible.  I have defined a point mass for the c.o.m. of each puck. I have defined another point mass for the small offset dot, I can keep changing references to the c.o.m. to each puck and analyze the angular motion. Not too daunting a task but I was wondering if I am missing something obvious about this scenario that I might be able to use.

Is there a way to define an orientation vector between the c.o.m. of a puck and the corresponding offset mark?  Then I can simply chart the rotation? Would provide a nice visual.




1. We have Tracker 5.0 deployed on Linux machines in our classroom.