so 0 0 An small object of mass m1 moves in a circular path of radius r on a frictionless horizontal tabletop (Figure 5-72). It is attached to a string that passes through a small frictionless hole in the center of the table. A second object with a mass of m2 is attached to the other end of the string. Derive an expression for r in terms of m1, m2, and the time T for one revolution. m 2! 1