Hi, I am new to the FES and I have some questions about how pendulums work in FET. I do want to disclaim that I am not attacking FET nor am I trying to disprove it, I just enjoy having knowledge.

When a pendulum is in a free moving system the parabolic arc made by the object at the end of the rope begins to rotate on the equilibrium point. According to RET this is because of the rotation of the earth. Being that the rotation of the earth acts very little on a system in free fall, the pendulum will not stay in one parabolic arc.

Does the parabola move in flat earth theory because the disk is rotating? I assume not because, well, it does not rotate.
Regardless, either a link to an article explain this phenomenon in FET or just a plain answer would be very much appreciated.
Thanks!