Help with an object, swinging from an elastic rope

Been googling and code-archiving for this, but nothing yet. I need a prod in the right direction: the algorithms needn't be perfect, a quick-n-dirty solution that looks convincing enough is fine.

I need a formula/algorithm for an object swinging from an elastic rope with variable elasticity.

Anyone know a place I can do reading up on this?

I'd suggest searching for a suitable physics engine, as I suspect there won't be a "quick'n'dirty" solution for this..
Atleast not if you're going to have (variable) elasticity on the rope.

There are two potential topics to search for that.

Either particle based physics ("atom physics")

or classical mechanics / newtonian physics

But I agree with LarsG, check the boards, there are several wrapper to well known physics engine and even some from ground up selfwritten ones.