( Weight ( ( refers ( to ( ( the force ) ( of ( gravity ( exerted ( on ( the object ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Weight)) (VP (VBZ refers) (PP (TO to) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBN exerted) (PP (IN on) (NP (DT the) (NN object))))))))) (. .)))
Weight refers to the force of gravity exerted on the object.
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity))))) (. .)))