Momentum: types of collision

Just a little summary about collision. Remember initial momentum is always equal to final momentum.

There are 3 types of collision:

Perfectly Elastic collisions

Perfectly Elastic collisions are surprisingly common. All collisions between atoms are Perfectly Elastic according to the Kinetic Theory of Gases.

• All momentum is conserved (not surprisingly - it always is!)
• Kinetic energy is conserved (that's what makes this special).
• Relative speed of approach = relative speed of separation.

(So if one is catching the other at 10m/s before the collision, it will be moving apart from it at 10m/s after the collision)

Perfectly Inelastic collisions

• All momentum is conserved (as always).
• Kinetic energy is not conserved.
• The relative speed of separation is zero.

 that means the objects stick together after the collision so just consider them as one object whose mass is the same as that of the two original masses combined.

Inelastic collisions

• All momentum is conserved (again).
• Kinetic energy is not conserved (again).
• You can't say anything about the speed at which they leave each other without doing a calculation                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            Sevani Persaud.