MC hitting the 'ground'

i have a php page where i am loading various swfs.

i want 2 MCs which will be placed in 1 swf (or 2, depending) to ‘fall’ from the top of the screen and land with a thud and a little random bounce.
the objects need to appear very heavy. I can do this manually, like with frames, but before I do, I am interested in finding out about doing this in AS in a way where each time the object falls the way it hits the horizon line is randomized. I mean the way it bounces slightly.
This will be accompanied by a sound-- imagine a steel plate falling and hitting the pavement (in a 2D world) and then bouncing slightly.

Any suggestions?