The following simulation show 10 sets of different particles, where there are different mass ratio.
All the m1 particles start with the same velocity, all the m2 particles are at rest(default) initialize.
You can drag v1 or v2 slider to change their initial velocity.
The simulation will show the mass ratio and velocity ratio after elastic collision.
While keep v2=0; what will you found the velocity ratio after the collision?
What other rules you have noticed?
You might want to check out [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1435.0]Elastic Collision (1D)[/url]