The figure shows a rigid structure consisting of a circular hoop of radius R and mass m, and a square made of four thin bars, each of length R and mass m. The rigid structure rotates at a constant speed about a vertical axis, with a period of rotation of 1.1 s. If R = 0.9 m and m = 4.2 kg, calculate the angular momentum about that axis

The figure shows a rigid structure consisting of a circular hoop of radius R and mass m, and a square made of four thin bars, each of length R and mass m. The rigid structure rotates at a constant speed about a vertical axis, with a period of rotation of 1.1 s. If R = 0.9 m and m = 4.2 kg, calculate the angular momentum about that axis