Find the kinetic energy of the system with one incoming ball of m m and speed v.?

A fun device that illustrates conservation of momentum and conservation of kinetic energy is the so-called executive stress reliever. It consists of five identical hard supported by strings of equal lengths. When one ball is pulled out and released, an almost-elastic collision causes one ball to move out on the opposite side with the same speed as the incoming ball. If two are pulled out and released, two swing out on the opposite side and so forth-but how do the “know”? For example, is it possible that, on occasion, when one ball is released, two will swing out on the opposite side traveling half the speed of the incoming ball? When you have convinced yourself that it is not going to happen, find the kinetic energy of the system with one incoming ball of m m and speed v and the kinetic energy of two outgoing with m m and speed v/2 to show that kinetic energy is not conserved in such collision.