Hello, the problem I am working on is: "A puck of mass [itex]m = 51.0 g [/itex]is attached to a taut cord passing through a small hole in a frictionless, horizontal surface (see figure below). The puck is initially orbiting with speed [itex]v_i = 1.30 m/s[/itex] in a circle of radius [itex]r_i = 0.310 m[/itex]. The cord is then slowly pulled from below, decreasing the radius of the circle to [itex]r = 0.120 m[/itex]." In the problem, it states that the surface is friction-less, so what would counterbalance the tension force in the string, so that the puck wouldn't be pulled completely towards the hole in the center of the table? Is it the centrifugal force (or, inertial force)? If so, could someone give me a descriptive answer as to why it is the centrifugal acting.