A horizontal turntable rotates about a fixed vertical axis. Its moment of inertia, excluding two identical small masses, is $0.40\ \mathrm{kg\,m^2}$ The masses are moved inward by radial forces through the axis. The bearing exerts negligible torque about the vertical axis. Treat the masses as point particles and the arms as having negligible mass.

Figure 1 shows the initial and final positions of the masses.