Is Newton's Law of Restitution Accurate for Eccentric Impacts?

[aim1732]

I have used Newton's law of restitution without problem in collisions between point objects but there seems to be a problem in its application in eccentric impacts.
I have always thought it is applied to points on rigid extended bodies that come in contact during the collision for eccentric collisions.[applied here implying their velocities are considered in the equation--
(-velocity of separation/velocity of approach) = e ]
But I recently came across suggestions on this forum that velocities of centres of mass of the extended objects is to be considered instead. Am I getting it wrong? Regrets if I am asking a stupid question...
For reference here is the link to the thread:
https://www.physicsforums.com/showthread.php?t=435457"

 

[Doc Al]

I have used Newton's law of restitution without problem in collisions between point objects but there seems to be a problem in its application in eccentric impacts.
I have always thought it is applied to points on rigid extended bodies that come in contact during the collision for eccentric collisions.[applied here implying their velocities are considered in the equation--
(-velocity of separation/velocity of approach) = e ]
But I recently came across suggestions on this forum that velocities of centres of mass of the extended objects is to be considered instead. Am I getting it wrong?

I'd say that you are correct, as long as you mean the normal components of the contact velocities. (I haven't looked at that thread.) You'd only use the velocities of the centers of mass for point objects.

 

[aim1732]

I'd say that you are correct, as long as you mean the normal components of the contact velocities.

Yes I meant the normal components.

Thanks a lot!