16. Angular Momentum

Two identical particles have equal but opposite momenta, $\overrightarrow{p}$ and $-\overrightarrow{p}$, but they are not traveling along the same line. Show that the total angular momentum of this system does not depend on the choice of origin.

Two lightweight rods 24 cm in length are mounted perpendicular to an axle and at 180° to each other (Fig. 11–35). At the end of each rod is a 480-g mass. The rods are spaced 42 cm apart along the axle. The axle rotates at 4.5 rad/s.

(a) What is the component of the total angular momentum along the axle?

(b) What angle does the vector angular momentum make with the axle? [Hint: Remember that the vector angular momentum must be calculated about the same point for both masses, which could be the cm.]