( ( The experiments ) ( ( showed ( that ( ( ( the force ) ( of traction ) ) ( ( ( was nearly ) ( in ( an ( exact proportion ) ) ) ) ( to ( ( the hardness ) ( of ( the road ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS experiments)) (VP (VBD showed) (SBAR (IN that) (S (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN traction)))) (VP (VBD was) (ADVP (RB nearly)) (PP (IN in) (NP (DT an) (JJ exact) (NN proportion))) (PP (TO to) (NP (NP (DT the) (NNS hardness)) (PP (IN of) (NP (DT the) (NN road))))))))) (. .)))
The experiments showed that the force of traction was nearly in an exact proportion to the hardness of the road.
(ROOT (S (NP (NNS Experiments)) (VP (VBP have) (VP (VBN shown) (SBAR (IN that) (S (NP (NN acceleration)) (VP (VBZ is) (ADVP (RB exactly)) (ADVP (RB inversely) (NP (CD proportional)) (PP (TO to) (NP (NN mass)))) (, ,) (SBAR (RB just) (IN as) (S (NP (PRP it)) (VP (VBZ is) (ADVP (RB exactly)) (ADJP (RB linearly) (JJ proportional) (PP (TO to) (NP (DT the) (JJ net) (JJ external) (NN force)))))))))))) (. .)))