( Impulse ( ( is ( ( the change ) ( in momentum ) ) ) . ) )
(ROOT (S (NP (NNP Impulse)) (VP (VBZ is) (NP (NP (DT the) (NN change)) (PP (IN in) (NP (NN momentum))))) (. .)))
Impulse is the change in momentum.
(ROOT (S (NP (NP (NNP Change)) (PP (IN in) (NP (NP (NN momentum)) (PP (IN in) (NP (DT an) (NN object)))))) (VP (VBZ is) (ADJP (JJ equivalent) (PP (TO to) (NP (NN impulse))))) (. .)))