I'm trying to simulate a rollercoaster game with ActionScript 3, but i don't know exactly if I should use a 2d engine (like Box2d) or do it from scratch.
For any of those I would like to see some code example.
Any ideas, pointers, suggestions... Thanks in advance!
I think that you should Box2D, and you can read documentation on official site. Try make Hello World example and you can see all power of this physics library. http://www.box2d.org/manual.html