The discussion revolves around the concepts of angular energy and translational energy in the context of a rectangular block tipping over a pivot point. Participants explore the conditions under which the block exhibits rotational and translational kinetic energy as it falls to the ground.
There is an active exploration of the relationship between translational and rotational kinetic energy, with participants providing insights into how friction influences these energies. Some participants express understanding of the concepts, while others continue to seek clarification on specific scenarios, such as the effects of friction and the conditions for translational motion.
Participants are considering various scenarios, including the presence or absence of friction and the implications for the block's motion. There is an emphasis on understanding the roles of the center of mass and the pivot point in determining the energy types involved.
GnG.Vike13 said:so the translational kinetic energy is based on its center of mass' velocity and the rotational energy is based on the I of the whole block and w?
and, just to be clear, the weight vector will always come from the center of mass, correct?
also, how would friction play into this? would it be at the axis of rotation, thus causing not torque, but preventing it from making a translational acceleration?
sophiecentaur said:That seems the right idea. But there would be a definite difference if there were no friction. What would the block rotate around if the corner were allowed to slip? Would the cm ever be moving horizontally at all? Would the block take the same time to fall with and without friction?
Your statements about mvsquared/2 and Iωsquared/2 are obviously correct. I think the only way that there would be no translational energy would be if it were just a couple that was applied to the block so that the cm was not moving in any direction. This is definitely not the case here.