( Centripetal ( ( forces 5 ) . ) )
(ROOT (S (NP (NNP Centripetal)) (VP (VBZ forces) (NP (CD 5))) (. .)))
Centripetal forces 5.
(ROOT (S (NP (JJ Centripetal) (NN force)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (SBAR (WHNP (WDT that)) (S (VP (VBZ causes) (NP (JJ centripetal) (NN acceleration))))))) (. .)))