Identical Particles Are Placed at the 50-Cm and 80-Cm Marks

Multiple Choice

Identical particles are placed at the 50-cm and 80-cm marks on a metre stick of negligible mass. This rigid body is then mounted so as to rotate freely about a pivot at the 0-cm mark on the metre stick. If this body is released from rest in a horizontal position, what is the angular speed of the metre stick as it swings through its lowest position?

A) 4.2 rad/s
B) 5.4 rad/s
C) 4.6 rad/s
D) 5.0 rad/s
E) 1.7 rad/s