1. The problem statement, all variables and given/known data The problem is: The ball B is travelling on a horizontal circle table. It is attached to the string that leads through a hole in the center of the circle. At the very beginning, the ball B is travelling around a circular path counter-clockwise, then the cord is pulled down through the hole with a constant speed. Sketch both polar coordinate and normal-tangential coordinates. 2. Relevant equations 3. The attempt at a solution My issues lie with understanding what the normal and tangential coordinates would be in this case. Would Uθ and Ut be the same in this case? Also for the Un would it just be parallel to the axis in the center and go through the ball? Or am I thinking about this wrong and is it just a simple 2D circular motion still.