13. Two thin rods of negligible mass are rigidly attached at their ends to form a 90° angle. The rods rotate in the xy plane with the joined ends forming the pivot at the origin.
A particle of mass 75 g is attached to one rod a distance of 42 cm from the origin, and a particle of mass 30 g is attached to the other rod a distance of 65 cm from the origin.
(a) What is the rotational inertia of the assembly?
(b) How would the rotational inertia change if the particles were both attached to one rod at the given distances from the origin?