( ( ( Exerting ( considerable force ) ) ( to ( complete ( ( a motion ) ( -LRB- ( i.e. ( , ( ( forceful exertions ) -RRB- ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VBG Exerting) (NP (JJ considerable) (NN force)) (S (VP (TO to) (VP (VB complete) (NP (NP (DT a) (NN motion)) (PRN (-LRB- -LRB-) (FW i.e.) (, ,) (ADJP (JJ forceful) (JJ exertions)) (-RRB- -RRB-))))))) (. .)))
Exerting considerable force to complete a motion (i.e., forceful exertions).
(ROOT (S (NP (NNP Work)) (VP (VBZ is) (VP (VBN done) (SBAR (RB only) (IN if) (S (NP (DT a) (NN force)) (VP (VBZ is) (VP (VBN exerted) (PP (IN in) (NP (NP (DT the) (NN direction)) (PP (IN of) (NP (NN motion))))))))))) (. .)))