( ( The ( position-time graph ) ) ( ( shows ( that ( ( the slope ) ( is ( ( ( ( changing ( -LRB- ( ( meaning ( a ( changing velocity ) ) ) -RRB- ) ) ) and ) negative ) ( -LRB- ( ( meaning ( a ( negative velocity ) ) ) -RRB- ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ position-time) (NN graph)) (VP (VBZ shows) (SBAR (IN that) (S (NP (DT the) (NN slope)) (VP (VBZ is) (ADJP (ADJP (JJ changing)) (PRN (-LRB- -LRB-) (S (VP (VBG meaning) (NP (DT a) (VBG changing) (NN velocity)))) (-RRB- -RRB-)) (CC and) (ADJP (JJ negative)) (PRN (-LRB- -LRB-) (S (VP (VBG meaning) (NP (DT a) (JJ negative) (NN velocity)))) (-RRB- -RRB-))))))) (. .)))
The position-time graph shows that the slope is changing (meaning a changing velocity) and negative (meaning a negative velocity).
(ROOT (S (PP (IN In) (NP (DT a) (JJ position-time) (NN graph))) (, ,) (NP (NP (DT the) (NN slope)) (PP (IN of) (NP (DT the) (NN line)))) (VP (VBZ represents) (NP (DT the) (NN velocity))) (. .)))
In a position-time graph, the slope of the line represents the velocity.