( ( Consider ( ( a ( one-dimensional ( elastic collision ) ) ) ( between ( particles ( of ( masses and ) ) ) ) ) ) . )
(ROOT (S (VP (VB Consider) (NP (NP (DT a) (JJ one-dimensional) (JJ elastic) (NN collision)) (PP (IN between) (NP (NP (NNS particles)) (PP (IN of) (NP (NNP masses) (NNP and))))))) (. .)))
Consider a one-dimensional elastic collision between particles of masses and .
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN gas) (NNS particles)) (VP (VBP collide)))) (, ,) (NP (DT these) (NNS collisions)) (VP (VBP are) (VP (VBN considered) (S (ADJP (JJ elastic))))) (. .)))