Athin-walled, starts from rest and rolls without slipping down a track (Fig. P10.72). Points A and B are on a circular part of the track having radius R. The diameter of the shell is very small compared to h0 and R, and the work done by rolling friction is negligible. (a) What is the minimum height h0 for which this shell will make a complete loop-the-loop on the circular part of the track