( ( The beginning ) ( ( was ( defined ( as ( ( the moment ) ( ( at which ) ( ( ( the velocity ) ( of ( the ( ( eye or ) hand ) ) ) ) ( exceeded ( ( 10 % ) ( of ( peak velocity ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN beginning)) (VP (VBD was) (VP (VBN defined) (PP (IN as) (NP (NP (DT the) (NN moment)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (NP (DT the) (NN velocity)) (PP (IN of) (NP (DT the) (NN eye) (CC or) (NN hand)))) (VP (VBD exceeded) (NP (NP (CD 10) (NN %)) (PP (IN of) (NP (JJ peak) (NN velocity))))))))))) (. .)))
The beginning was defined as the moment at which the velocity of the eye or hand exceeded 10% of peak velocity.
(ROOT (S (NP (JJ Instantaneous) (NN velocity)) (VP (VBZ is) (VP (VBN defined) (PP (IN as) (NP (NP (DT the) (NN velocity)) (PP (IN of) (NP (DT the) (NN object))))) (PP (IN at) (NP (DT a) (VBN given) (NN moment))))) (. .)))