(1) A solid sphere of mass m and radius r rolls without slipping along the track shown below. It starts higher than r. Find the minimum value of A (in terms of A) such that the sphere completes the loop, with the lowest point of the sphere at height h above the bottom of the loop of radius R much larger than r. Find the minimum value of A in terms of R such that the sphere completes the loop.
Solid sphere of mass m and radius << R.