an abstract class of model fragments whose sole purpose is to have the gravitational acceleration due to earth.
the gravitational acceleration on earth
(Forall (?Self ?Time) (=> (Active ?Time Earth-Bound-Model ?Self) (= (Lambda (?T) (If (= ?T ?Time) (Value-At (Acceleration-Due-To-Gravity ?Self) ?T))) 9.81))) (Forall (?Self ?Time) (<=> (Active ?Time Earth-Bound-Model ?Self) (Earth-Bound-Model ?Self))) (=> (Earth-Bound-Model ?Self) (Quantity.Dimension (Acceleration-Due-To-Gravity ?Self) Acceleration-Dimension))