( ( The weight ) ( ( is ( ( the force ) ( of ( gravity ( pulling ( on ( that mass ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN weight)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBG pulling) (PP (IN on) (NP (DT that) (NN mass)))))))) (. .)))
The weight is the force of gravity pulling on that mass.
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (NN measure)) (PP (IN of) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBG pulling) (PRT (RP down)) (PP (IN on) (NP (DT an) (NN object)))))))))))) (. .)))