( ( Centrifuges ( ( do n't ) ( increase gravity ) ) ) ( , ( ( ( the ( centrifugal force ) ) ( caused ( by inertia ) ) ) ( ( is ( what ( causes ( ( ( the effect ) ( of ( 9 g ) ) ) 's ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (NNS Centrifuges)) (VP (VBP do) (RB n't) (VP (VB increase) (NP (NN gravity))))) (, ,) (NP (NP (DT the) (JJ centrifugal) (NN force)) (VP (VBN caused) (PP (IN by) (NP (NN inertia))))) (VP (VBZ is) (SBAR (WHNP (WP what)) (S (VP (VBZ causes) (SBAR (S (NP (NP (DT the) (NN effect)) (PP (IN of) (NP (CD 9) (NN g)))) (VP (VBZ 's)))))))) (. .)))
Centrifuges don't increase gravity, the centrifugal force caused by inertia is what causes the effect of 9 g's.
(ROOT (S (NP (NNS Centrifuges)) (VP (VBP use) (NP (NN inertia)) (S (VP (TO to) (VP (VB perform) (NP (PRP$ their) (NN task)))))) (. .)))