I have a formula, S*r=1/2*m*r^2*a/r The problem is that it is unlabeled, and I am not 100% sure what this is supposed to be for. As near as I can tell, it is for something with inertia, and involving tension on a wire coiled around a cylinder. Is this correct? Does anyone know if this is simply a derived equation for a specific problem, or a general use equation? Thank you.