With a pendulum in motion,(Given Mass (X) in motion), contained within a static gravitaional field(Restrained by given Grav Field)

Suddenly, we reduce Grav field, (some small quantity) (IE by eclipse)
The (kinetic) Mass would remain constant, and be restrained less, increasing speed and length of arc

I'm running this mind experiment, where we have this pendulum swinging away in a given grav field and suddenly in mid swing we bring an opposing grav field over top of it...(Say the moon at an altitude of 20,000 Miles). the pendulum is now in Zero grav, and (still containing its momentum) it starts circling around the "fulcrum" pivot point of the pendulum endlessly...