/sci/ - Science & Math

Newton's cradle consists of five equal-sized steel balls that hang in a stand (see figure). The balls can be pulled out to the side and released, whereupon they collide elastically with the other balls. If two of the balls are pulled to the side and released, two balls are fired on the other side as the figure shows. The momentum would be preserved even if only one balls was fired on the other side but at double the speed (compared to the two balls). Why does it never happens in the real world, how could I show this through calculations?