Question

A single propeller is rotating without friction at a constant angular velocity. Treat the propeller as a single, uniform rod that is freely (viz., there is no engine) rotating about its center. A bird has built a nest above the propeller, which is prime real estate except for the constant draft coming from the propeller. The bird, having an impressive grasp of mechanics, decides to land softly and deftly on the propeller so as to reduce its angular velocity. At what point on the propeller should the bird land so as to reduce its angular velocity by 50.0%? The bird and the rod have the same mass. Assume that the propeller is oriented horizontally, and that as the bird lands on it he or she is moving vertically. Find this distance in terms of the masses of the bird and propeller, and the propeller’s length.

Answer 1

We know without any torque angular momentum will remain constant for a body. Now anguler momentum is expressed as L = Iw