A smooth uniform rod of length L and mass M has two identical beads of negligible size each of mass m which can slide freely along the rod. Initially the two beada are at the centre of the rod and the system is rotating with an angular velocity `omega_0` about an axis perpenducular to the rod and passing through the midpoint of the rod. There are no external forces. When the beads reach the ends of the rod, the angular velocity of the system is ......

Answer

A

Explanation

Since no external force and hence no torque is applied
the angular momentum remains constant
`:. I_1 omega_1 = I_2 omega_2`
`:. omega_2 = (I_1omega_1)/(I_2) = ((ML^2)/(12)xxomega_0)/((ML^2)/(12) +2mxx((L)/(2))^2) = (Momega_0)/(M+6m)`