Question

Two pieces of clay of equal mass move with equal speed, but in opposite directions on a frictionless surface. If both collide head-on. What happens to the cinetic energy?

Answer 1

Since both pieces of clay are of equal masses and are moving in opposite direction therefore their momentum vectors will be equal in magnitude but opposite in sign .Thus the total momentum of the system is zero.Since during collision no external force acts on the system therefore their momentum after collision will also be zero . Hence the speed of the combined clay Mass after collision is zero. so show the kinetic energy of the system become zero and entire initial kinetic energy of the system lost as heat and sound produced during collision or is spent on the the deformation of the clay mass