Quote:
Two identical 1kg objects, each travelling at 4000m/s collide head on and stick together. After they stick together you say the 2kg blob will be moving at 4000m/s.


its a good thing we were discussing an elastic collision otherwise you would be correct.

http://en.wikipedia.org/wiki/Elastic_collision

Quote:
An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter. Elastic collisions occur only if there is no net conversion of kinetic energy into other forms.

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.