( This ( ( is ( one ( of ( ( those ( inelastic collisions ) ) ( where ( momentum ( ( is not ) conserved ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT those) (JJ inelastic) (NNS collisions)) (SBAR (WHADVP (WRB where)) (S (NP (NN momentum)) (VP (VBZ is) (RB not) (ADJP (JJ conserved))))))))) (. .)))
This is one of those inelastic collisions where momentum is not conserved.
(ROOT (S (NP (DT A) (ADJP (RB perfectly) (JJ inelastic)) (NN collision)) (VP (VBZ reduces) (NP (JJ internal) (JJ kinetic) (NN energy)) (PP (TO to) (NP (NP (DT the) (NN minimum)) (SBAR (S (NP (PRP it)) (VP (MD can) (VP (VB have) (NP (NN while)) (ADVP (RB still)) (S (VP (VBG conserving) (NP (NN momentum))))))))))) (. .)))