Is there a way to predict the motion of a non-rigid body?
If you drop a cat on the sofa, you can easily predict that it will land paws-down.
Can you be more specific with your question?
Well what I mean is, we have all kinds of formulas for rigid bodies, can we just apply them to a non-rigid or fluid body, or are there different mechanics for non-rigid/fluid bodies?
The mechanics are the same. The math, however, becomes more complicated.
Center of mass motion is exactly the same for articulated or soft bodies. There is no general solution for other DoF, however. You'll have to write down the Lagrangian for the whole thing and see how you can go about solving it.
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