Quote:Original post by chand81

Quote:Original post by Numsgil
wether the collision is dead center or barely glancing, the change in linear momentum is the same.

I'm not sure I can agree on that statement.
Although the equation for change in linear velocity is the same even with angular effects considered, the equation for impulse J changes drastically. It now depends on the collision point. So for a dead center collision J will be large and for a barely glancing collision J will be very small unless there is friction (in which case the direction of J changes). And when J changes, so does the change in velocity/momentum.

Hmm, I see your point. I made that statement remembering my college physics instead of looking at the equation being used. I'm pretty sure I'm right-- the only thing that changes the corrective impulse is the velocity of the contact points. I'm guessing maybe the position terms cancel in some way, but I don't see how. Either that, or I've been wrong for a long time ;)

Also, if the point of contact mattered beyond determining linear velocity caused by rotation (and maybe the collision normal), wouldn't Hecker have a different equation for 3.6? So I'm not sure. And I'm a little too tired for a formal examination.

As far as conservation of angular momentum... This page might be useful. It's talking about basically the same sort of collision response system. The notation is a little dense, but they show how angular momentum is conserved.

I'm afraid this might be a case where I know a subject well enough for my own purposes, but not well enough to teach it :P