1. The problem statement, all variables and given/known data A small block of mass 0.91 kg slides without friction on a horizontal table. Initially it moves in a circle of radius r0 = 0.63 m with a speed 1.5 m/s. It is held in its path by a string that passes through a small hole at the center of the circle. The string is then pulled down a distance of r0 - r1 = 0.12 m, leaving it at a radius of r1 = 0.51 m. It is pulled so slowly that the object continues to move in a circle of continually decreasing radius. How much work was done by the force to change the radius from 0.63 m to 0.51 m? 2. Relevant equations W net = mv f 2 - mv o 2 3. The attempt at a solution I tried to use the work energy theorem, but I'm confused because I think I'm getting the wrong numbers? Can anybody guide me?