( Motion ( ( is ( change ( in position ) ) ) . ) )
(ROOT (S (NP (NNP Motion)) (VP (VBZ is) (NP (NP (NN change)) (PP (IN in) (NP (NN position))))) (. .)))
Motion is change in position.
(ROOT (S (NP (NNP Motion)) (VP (MD can) (VP (VB be) (VP (VBN defined) (ADVP (RB simply)) (PP (IN as) (NP (NP (DT a) (NN change)) (PP (IN in) (NP (NN position)))))))) (. .)))