Once the marble is let go, the force of gravity (a pulling force) releases the potential of the marble to drop and the marble drops the established distance or height.
(the marble; is let; T:Once) (the marble; drops; the established distance or height) (the marble; go; ) (the force of gravity; releases; the potential of the marble; T:Once the marble is let go)
the marble the marble the marble the force of gravity
is let drops go releases
T:Once
the established distance or height
the potential of the marble T:Once the marble is let go