It is just as instructive to use the Interactive Physics program to study elastic collisions as inelastic ones. When you finish this simulation you should be able to tell:
Open the simulation file "Elastic Collisions 99". You should see the screen shown below.
(This simulation is "packaged", since Interactive Physics won't easily display object's velocities relative to the system's center of mass - it has to be "programmed" to do so. If you are interested in how this works, I'll be happy to show you.)
You can set the mass and initial velocity of each object using the sliders on the right side of the screen. The velocities of the objects and the center of mass is shown on the left, in both the "earth" and center of mass frames of reference. You can view the collision in either frame of reference by clicking the buttons at the bottom right. ("Home" is the earth frame of reference.)