Elastic collisions inside a hollow cilinder

[gabrielbhl]

Hi everybody.
That's my first (of many) post here!
I'm a brazilian guy who is trying o solve de Wopho's Problems.
And onde of then called my attention for the criativity using an (theoterically) easy concept of elastic collision.
The problem is the second http://wopho.org/selection-downloadproblem.php?id=3

I have an hollow cylinder and an disc inside it with V_o and I (and the problem) ask you what wiil happens after de collisions (that is: the velocity of the disc and cylinder after the first e nth collision)
I'm really needing some help in this excellent problem, but that is not my homework, and yes a good problem which requires reasonig.
Any idea??

Thank's for the attention and sorry for my bad english!

 

[gabrielbhl]

I've tryied using theta=0 and then put some sen and cos but I failed!



In my opinion, that is the best collision problem ever

 

[gabrielbhl]

Anyone?? Please i need your help!

 

[nekronaut]

"The competition is for individuals, solutions sent by group of students are not accepted.

All participants must solve the problems individually. The problems can be downloaded from the problem section of the WoPhO Selection Round webpage"