A bullet of mass mb kg is moving with a speed of v m/s when it collides with a rod of mass mr and length L m. The rod is initially at rest, in a vertical position, and pivots about an axis going through its center of mass which is located exactly halfway along the rod. The bullet imbeds itself in the rod at a distance L/4 from the pivot point. As a result, the bullet-rod system starts rotating together. What is the magnitude of the angular velocity of the rotation (in rad/s)