A homogeneous rod AB of length L= 1.8 m and mass M is pivoted at the centre O in such a way that it can rotate freely in the vertical plane. The rod is initially in the horizontal position. An insect S of the same mass M falls vertically with speed `nu`on the point C, mid-way between the points O and B. Immediately after falling, the insect moves towards the end B, such that the rod rotates with a constant angular velocity `omega`. Determine the angular velocity.