A solid steel ball of radius r rolls without slipping down an incline into a vertical loop of radius R. (just like the Hot Wheels setup used during the unit on Energy) In order to maintain contact with the track while at the top of the loop, the ball’s center of gravity must be moving at a minimum linear speed of . Find the height the ball must start relative to the bottom of the loop in order to stay on the track in terms of the other variables identified.