A wad of clay of mass m with initial horizontal velocity v hits and adheres to the massless rigid bar which supports the body of mass 3m, which can be assumed to be a particle. The pendulum assembly is freely pivoted at O and is initially stationary. (a) Is linear momentum of the system conserved? Why or why not? (b) Determine the angular velocity of the combined body just after impact (in terms of L, m and v).