Rotating Pendulum Z201 from System Zoo 1 p80-83
https://pt.wikipedia.org/wiki/P%C3%AAndulo / https://en.wikipedia.org/wiki/Pendulum
https://pt.wikipedia.org/wiki/Equa%C3%A7%C3%A3o_do_p%C3%AAndulo https://en.wikipedia.org/wiki/Pendulum_(mechanics)