We did a lab to illustrate this concept in class. The problem is I have no idea what this concept is trying to show. Basically the length of a string was altered from 30 cm to 80 cm. Then, at a 90 degree angle from the vertical of the pole housing the meter stick and the attached string, it was released with a metal circular object. D, the distance to the point where it wraps around a horizontal rod, was measured. The relationship that came about was D = (3/5)L. The issue that I don't understand is the use of Ma = T + Mg and a = (v^2)/r to derive D = (3/5)L. If anyone has an inkling of where I can get any physics info on this "concept" or if you can help, please respond. Thanks.