( ( ( The force ) ( due ( to ( gravity ( on ( a ( heavy object ) ) ) ) ) ) ) ( ( is ( called ( ( ( its weight ) , ) ( which ( depends ( on ( ( ( the ( local ( gravity field ) ) ) and ) ( its ( gravitational mass ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN force)) (ADJP (JJ due) (PP (TO to) (NP (NP (NN gravity)) (PP (IN on) (NP (DT a) (JJ heavy) (NN object))))))) (VP (VBZ is) (VP (VBN called) (NP (NP (PRP$ its) (NN weight)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ depends) (PP (IN on) (NP (NP (DT the) (JJ local) (NN gravity) (NN field)) (CC and) (NP (PRP$ its) (JJ gravitational) (NN mass)))))))))) (. .)))
The force due to gravity on a heavy object is called its weight , which depends on the local gravity field and its gravitational mass.
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity))))) (. .)))