( ( ( The coefficient ) ( of ( sliding friction ) ) ) ( ( is 0.75 ) . ) )
(ROOT (S (NP (NP (DT The) (NN coefficient)) (PP (IN of) (S (VP (VBG sliding) (NP (NN friction)))))) (VP (VBZ is) (NP (CD 0.75))) (. .)))
The coefficient of sliding friction is 0.75.
(ROOT (S (NP (VBG Sliding) (NN friction)) (VP (VBZ is) (NP (NP (NN friction)) (SBAR (WHNP (WDT that)) (S (VP (VBZ acts) (PP (IN on) (NP (NP (NNS objects)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VBP are) (VP (VBG sliding) (PP (IN over) (NP (DT a) (NN surface)))))))))))))) (. .)))