1. The problem statement, all variables and given/known data When you are spinning an object in a circular path, you are applying centripetal force towards the center of the circle while the velocity vector is perpendicular to it. Therefore the Force component affecting the velocity is FCos(90) = 0. Keeping this in mind, how can you make the object you are spinning move faster or slower? 2. Relevant equations V = rw , w = circuference/Period, F = ma 3. The attempt at a solution I am just generally confused by this fact, I tried holding a string and experimenting with it and I can deduce easily that I can change the speed of the circular motion by tightening/letting go a little bit of the string. Yet the question states that this is not possible as the component of the force is FCos(90) = 0 (Which I understand and agree with) Any help here guys? Any simplifications if possible??