I might be mistaken, but that sounds like a fluid flow problem. Unfortunately not something Carrara can do easily. It's the same kind of problem as having a furry ball bounce up and down and have the hair lag behind (as long hair would tend to do). Your only recourse in Carrara is to keyframe the entire thing, unless there's a plugin out there for it. Now if you could somehow model a very long chain with very small links in it, then it might appear to be a string...