A bullet of mass mb = 0.02 kg is moving with a speed of 100 m/s when it collides with a rod of mass mr = 5 kg and length L = 2 m. The rod is initially at rest, in a vertical position, and pivots about an axis going through its center of mass. The bullet imbeds itself in the rod at a distance L/4 from the pivot point and, as a result, the bullet-rod system starts rotating. What is the angular speed (in rad/s) of this rotation? Hint: you may treat the bullet as a point mass.