( ( ( ( ( Momentum ( is ( ( the product ) ( of ( ( velocity and ) mass ) ) ) ) ) , ) and ) ( ( in physics ) ( ( ( the idea ) ( of velocity ) ) ( ( is ( the speed ) ) ( that ( something ( is ( going ( in ( a ( certain direction ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Momentum)) (VP (VBZ is) (NP (NP (DT the) (NN product)) (PP (IN of) (NP (NN velocity) (CC and) (NN mass)))))) (, ,) (CC and) (S (PP (IN in) (NP (NN physics))) (NP (NP (DT the) (NN idea)) (PP (IN of) (NP (NN velocity)))) (VP (VBZ is) (NP (DT the) (NN speed)) (SBAR (IN that) (S (NP (NN something)) (VP (VBZ is) (VP (VBG going) (PP (IN in) (NP (DT a) (JJ certain) (NN direction))))))))) (. .)))
Momentum is the product of velocity and mass, and in physics the idea of velocity is the speed that something is going in a certain direction.
(ROOT (S (NP (NNP Momentum)) (VP (VBZ is) (ADJP (RB directly) (VBN related) (PP (TO to) (NP (NP (DT both) (NN mass)) (CC and) (NP (NN velocity)))))) (. .)))