1. The problem statement, all variables and given/known data A 39.00 kg rod of length 2.8 m is hanging vertically by one of its ends that is free to swing in a complete circle about a frictionless axle/pivot. The rod has uniform mass density. Suddenly it is struck horizontally by a 5 kg putty that sticks to the center of mass of the rod upon impact. With what minimum speed must the putty strike the rod so that the combination (of rod and putty) is just barely able to make a complete circular loop? 2. Relevant equations Lbefore=Lafter 1/2mpv2=1/2Iw^2 Where mp is the mass of the putty and I is for the system of the putty and the rod. 3. The attempt at a solution I know that I have to use conservation of angular momentum and the kinetic energy conservation, but I have no clue what the condition for "barely able to make a complete circular loop" is in relation to the final velocity, so I'm completely stuck.