Suppose you have 2 iron balls that are connected to one another by a bar. The balls have equal mass. The bar has a fixed length, has no mass, and cannot be compressed or stretched. The object is in a total void with no gravity or wind resistance. The balls can move on a 2D plain, the X,Y plain. The inputs are ball A and ball B's (x,y), mass, and the force, and direction of force applied on each. How do you find the outputs of the new (x,y) position for each iron ball? You can assume the iron balls have no volume just a weight, and the bar has no volume or weight, just a length. Outside motion is only applied on the point for each ball. (Outside motion isn't applied on the bar, but each ball affects the position of the other via the bar.) Basically the only function of the bar is keeping the two dumbells a fixed length apart. So any force in one end of the bar should effect the other end in someway. For example, we could start with a dumbell with it's first weight, A, on (0,0) and it's 2nd wieght, B, on (10,10). We apply upward force to B. If B weren't attached to A, B would go straight up. Given that B is attachedto A, when upward force is applied to B it should curve upward toward the y axis, and A should curve away from it's start point. I'd really like an equation or a set of equations that describe this. I imagine this is just could be done with just an application of Newton's laws.