( ( ( the ( net exchange ) ) ( of ( energy ( at equilibrium ) ) ) ) ( ( is zero ) . ) )
(ROOT (S (NP (NP (DT the) (JJ net) (NN exchange)) (PP (IN of) (NP (NP (NN energy)) (PP (IN at) (NP (NN equilibrium)))))) (VP (VBZ is) (NP (CD zero))) (. .)))
the net exchange of energy at equilibrium is zero.
(ROOT (S (NP (DT A) (VBG moving) (NN car)) (VP (VBZ is) (VP (VBN said) (S (VP (TO to) (VP (VB be) (PP (IN in) (NP (JJ dynamic) (NN equilibrium))) (SBAR (WHADVP (WRB when)) (S (NP (PRP it)) (VP (VBZ is) (NP (CD zero) (JJ net) (NN force)))))))))) (. .)))