Here is my problem: I'm a set designer for a show. I have a set piece of a tree that is 12ft. tall and sits on a 8' by 8' platform that is on wheels. The issue is that this tree has a swing that comes off of it. Someone who is about 100lbs will be swinging on the set piece. How heavy should the tree be so that her weight does not overcome the inertia of the tree platform? Also, if someone could walk me through the steps of finding the solution, that would by awesome. And if I didn't give you enough information, let me know, I'm new to this. Thanks guys!