5. A ball with mass m descends along a smooth curved track with the depicted shape (right). (a) To sustain circular motion without leaving the track, what is the minimum starting height from which the ball must initiate its descent? (b) At the highest point A of the H circular path, what are the forces acting on the ball? (c) If the ball B commences its slide from a height H = 2R, what will be its 7 subsequent motion