If there's a rigid rod in space, and you give some external force perpendicular to the rod at one of the ends for a short time, what happens?
Specifically: What dependence does the moment of inertia have? If it rotates, what is the center of rotation? Does it matter that the rod is rigid? What happens if it's "springy", say a rubber rod instead. Is there a difference between exerting a force for a short period of time, and having an inelastic collision (say a ball hits the end of the rod instead of you pressing).