No problem. Actually, I can see the dilemma you were in. I'm sure there's a better solution that the one I presented,
it just hasn't come to me yet. I knew the use of the variables would help expand your thought process. I've found there is always a solution, you just need something to hit you on the head. Just something to remember; you can create variables that are strings, and use those to define states like falling, bouncing, rolling, etc. And write
SYSTEM>COG_VARIABLE = FALLING > PLAY FALLING_SOUND and so on.....
also you can use "trigger once while true" with collisions, you just have to make the "trigger once while true" a sub event of the "on collision" condition.
I think I might expand on that capx a little and post tutorial about it.
Anyway, good luck!
I tried some variations, and I figured I will try to make it work like my sketch says (v=db). It will feel natural for faster rolling physical objects (tried it and failed right now). But it is more complex and I have some simplier matters to learn/attend to, like graphical resources for scenery, creating a custom fitting soundtrack for the game. There sheer amount of stuff you cand do, is overwhelming for a single project, but it is all managble, if you get what can-be-made-atm out of the way and then take your time to go threw the manual, examples and tutorials and nail those harder parts and learn them.
If you were to made a tutorial out of this, that would be awsome, but consider your own time first, because I think you have done more than enough right now!