Consider the roller-coaster car in Problem 37. At what minimum value of the starting height \(b\) above the ground must the car begin its journey if it is to remain on the track at the top of the loop?

Data from Problem 37

A roller-coaster car initially at a position on the track a height \(h\) above the ground begins a downward run on a long, steeply sloping track and then goes into a circular loop-the-loop of radius \(R\) whose bottom is a distance \(d\) above the ground (Figure P11.37). Ignore friction.

Data from Figure P11.37

KX- dx x