( Impulse ( ( ( is also ) ( described ( as ( ( the change ) ( in momentum ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Impulse)) (VP (VBZ is) (ADVP (RB also)) (VP (VBN described) (PP (IN as) (NP (NP (DT the) (NN change)) (PP (IN in) (NP (NN momentum))))))) (. .)))
Impulse is also described as 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))))) (. .)))