A thin uniform bar of length $L$ and mass $8$ m lies on a smooth horizontal table. Two point masses m and 2 m are moving in the same horizontal plane from opposite sides of the bar with speeds 2$\upsilon $ and $\upsilon $ respectively. The masses stick to the bar after collision at a distance ${L \over 3}$ and ${L \over 6}$ respectively from the center of the bar. If the br starts rotating about its center of mass as a result of collision, the angular speed of the bar will be :