The discussion revolves around the relationship between Newton's third law and the conservation of angular momentum, particularly in the context of systems of particles and collisions. Participants explore the nuances of how action-reaction forces relate to angular momentum conservation.
Participants do not reach a consensus; instead, they present multiple viewpoints regarding the implications of Newton's third law on angular momentum conservation, particularly in different contexts such as collisions.
The discussion reflects varying interpretations of the conditions under which angular momentum is conserved, particularly the role of force direction and external torque. There are unresolved aspects regarding the application of these principles in different scenarios.
Of course, in the special (&idealized) case of CONTACT forces, the joining line segment is of zero length, and hence, the conservation of total angular momentum is preserved anyhow we look at it...Shooting star said:I don't have the book right now with me, so I'm a bit unsure of exactly what you don't like. I presume that you are talking about system of particles. The third law states that the action and reaction forces are equal and opposite, but does not say that they lie along the line joining the particles. Only in the latter case will the total angular momentum of a system be conserved if the external torque is zero.
That's a typical case, yes.Shooting star said:So, the case you are talking about is more pertinent for collisions, it seems to me?