Re: [math-fun] QUESTION: Rolling a ball along a closed curve

Right: spinning is not permitted. (Though I wouldn't have called it "rolling".) --Dan On Jul 29, 2014, at 7:21 AM, Veit Elser <ve10@cornell.edu> wrote:

Spinning the ball about the vertical (z) axis, and not having it move in the xy-plane, is technically “rolling without slipping”. So unless you modify your question, the length of the shortest C is zero, if I’m allowed to put N and S where I choose, or pi, if N and S start on a vertical axis.