1
$\begingroup$

Newtons experimental law I. E velocity of approach is equal to velocity of separation (for the points on the two bodies where the collision takes place) for an elastic collision is applicable for both, when the line of impact of collision passes through both their centre of masses (where relative velocity of centre of masses is taken) as well as when the line of impact of collision doesn't pass though one or both the object's centre of masses (where relative velocity of the points on the two bodies where collision takes place, is taken) . In the latter case, the collision force has a torque about centre of mass and hence, Rotation is also involved. While the law can be proved for the first case, I couldn't find a proof for off center collisions. I wanted to know if a general proof exists or at least an intuitive reason for it

enter image description here

$\endgroup$
0
$\begingroup$

I think the intuitive reason for a 2d case is that you can resolve the velocity of the collision into two components, one being the head-on component and the other being parallel with the collision surface. The parallel component is going to be unchanged, and the head-on component will satisfy Newton's experimental law for a 1d collision, so the net effect will be to satisfy the collision rule.

$\endgroup$
  • $\begingroup$ Thank you sir for addressing to my doubt, I have slightly edited my question to convey my doubt better. I wanted to know how the law is still obeyed when a part of head on component of velocity is utilised to cause rotation $\endgroup$ – Sid Nov 14 '19 at 13:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.