So, since the newtons cradle is all about the conservation of momentum. I was wondering, when one ball is released from one side at a certain velocity, why doesn't two balls at the end swing, at half the original speed?
The usual steel balls used in the Newtons Cradle are efficiently elastic, meaning they don't lose a lot of energy as heat. This implies most of the energy is conserved. If some other non-elastic material was used, this wouldn't be the case.