This simulation shows a 1-dimensional collision between two objects. The elasticity determines the type of collision: 0 for a completely inelastic collision; between 0 and 1 for an inelastic collision; 1 for elastic, and >1 for superelastic, in which kinetic energy is added to the system at the point of collision. The small green dot represents the center-of-mass of the two balls.

Some things to investigate include:
1. Is momentum conserved in all cases? See if you can find a combination of masses, initial speeds, and elasticity that will produce a total momentum after the collision that is different from the total momentum beforehand. What must you conclude from this?
2. Under what circumstances is kinetic energy conserved?
3. Pay close attention to the motion of the center-of-mass during the collision. In general, the motion of the individual balls is changed by the collision. Is the same thing true for the center-of-mass? Explain this.