( Gravity ( ( ( ( ( ( ( exerts ( a force ) ) downward ) , ) ( called ( the weight ) ) ) and ) ( labeled w ) ) . ) )
(ROOT (S (NP (NNP Gravity)) (VP (VP (VBZ exerts) (NP (DT a) (NN force)) (ADVP (RB downward))) (, ,) (VP (VBD called) (NP (DT the) (NN weight))) (CC and) (VP (VBD labeled) (NP (NN w)))) (. .)))
Gravity exerts a force downward, called the weight and labeled w .
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity))))) (. .)))