Hi there, I've got a conceptual question about the normal force as applied to rotational motion. Suppose you have an object like a uniform disk. If the disk were set up so that its axis of rotation were about its centre of mass, it would just sit there and the normal force would be equal to +mg. What happens if the disk is instead hinged so that its axis of rotation is at its rim (see attached image)? Here if the disk is held horizontally and then released, it'll experience an angular acceleration and start to rotate. Ultimately were it frictionless, it would oscillate back and forth. My question is what happens to the normal force in this situation? Does it remain equal to mg since ultimately the hinge isn't accelerating? Or, does the normal force decrease since the centre of mass of the disk is accelerating downwards. Or am I totally confused? Thanks! Chris.