software for simple rotional motion simulation

[east]

i need simple software tool to test circular motions or dynamics. i have seen some really higly souped up ones, but i want just a simple animation given inputs such as gravity, radius, speed etc etc. even one without the animation or graphics is fine.

 

could someone recomend a good flexible software for this purpose please. i don't want to have to handle sophisticated CAD software. by the time i'm done learning the software i would have forgotten why i needed it in the first place.