Two identical uniform rods OA and OB each of length $\mathcal{l}$ and mass m are connected to each other by a massless pin connection (both the rods can rotate about O which is free to move), that allows free rotation. The assembly is kept on a frictionless horizontal plane. Now two point masses each of mass m moving with speed u perpendicular to the AB and hit the assembly inelastically at points A and B as shown in the figure.