( ( A body ) ( ( ( remains ( at ( ( ( ( rest , ) or ) ( moves ( in ( ( a ( straight line ) ) ( -LRB- ( ( at ( a ( constant velocity ) ) ) -RRB- ) ) ) ) ) ) , ) ) ) ( unless ( ( acted upon ) ( by ( a ( net ( outside force ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN body)) (VP (VBZ remains) (PP (IN at) (NP (NP (NN rest)) (, ,) (CC or) (NP (NP (NNS moves)) (PP (IN in) (NP (NP (DT a) (JJ straight) (NN line)) (PRN (-LRB- -LRB-) (PP (IN at) (NP (DT a) (JJ constant) (NN velocity))) (-RRB- -RRB-))))) (, ,))) (SBAR (IN unless) (S (VP (VBD acted) (PRT (RP upon)) (PP (IN by) (NP (DT a) (JJ net) (JJ outside) (NN force))))))) (. .)))
A body remains at rest, or moves in a straight line (at a constant velocity), unless acted upon by a net outside force.
(ROOT (S (SBAR (IN If) (S (NP (DT no) (JJ unbalanced) (NN force)) (VP (VBZ acts) (PP (IN on) (NP (DT an) (NN object)))))) (NP (DT the) (NN object)) (VP (VBZ remains) (PP (PP (IN at) (NP (JJ constant) (NN velocity))) (CC or) (PP (IN at) (NP (NN rest))))) (. .)))