Trajectories of the system (3.15)-(3.16) projected onto the subspace of variables for an eccentric ball of Group IIa with friction . The bold curves are the intermediate states (5.10). The curves , , and in -plane represent the curves on which the initial value of is chosen. The starting angle is . The arrows indicate the final position. Points on the plane are stable if , unstable otherwise. Trajectories are attracted to a noninverted position on the plane for , or they reach a point on the red curves otherwise. Two trajectories are added to illustrate the initial wild oscillations when is not chosen on one of the curves. We used , , , and .
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