( He ( also ( ( ( introduced here ) ( ( his ( vitally ( important criticism ) ) ) ( of ( ( the idea ) ( that ( ( changes ( in motion ) ) ( are ( ( the ( only effects ) ) ( of ( ( the exertion ) ( of force ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (PRP He)) (ADVP (RB also)) (VP (VBD introduced) (ADVP (RB here)) (NP (NP (PRP$ his) (JJ vitally) (JJ important) (NN criticism)) (PP (IN of) (NP (NP (DT the) (NN idea)) (SBAR (IN that) (S (NP (NP (NNS changes)) (PP (IN in) (NP (NN motion)))) (VP (VBP are) (NP (NP (DT the) (JJ only) (NNS effects)) (PP (IN of) (NP (NP (DT the) (NN exertion)) (PP (IN of) (NP (NN force))))))))))))) (. .)))
He also introduced here his vitally important criticism of the idea that changes in motion are the only effects of the exertion of force.
(ROOT (S (NP (NNP Work)) (VP (VBZ is) (VP (VBN done) (SBAR (RB only) (IN if) (S (NP (DT a) (NN force)) (VP (VBZ is) (VP (VBN exerted) (PP (IN in) (NP (NP (DT the) (NN direction)) (PP (IN of) (NP (NN motion))))))))))) (. .)))