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.