### Dynamics+Relative Constraints

Is it possible to do dynamics on mechanisms having absolute/relative distance constraints. relative x and relative y constraints, etc.?

Basically, in kinematics, we could model different aspects of a mechanism and leave certain bodies out of the model and replace them with relative constraints or absolute distance constraints. I'm wondering if one can study dynamics this way, or do we have to have all the bodies present in dynamics analysis? I assume all bodies will be present in a dynamics analysis, since each has mass and inertia contributing to the dynamics, however, for the final exam, you want us to have absolute distance as one of our constraints. So I am confused as to what constraints we can do dynamics on.

Thanks,

Matthew T