( ( ( The ( particle 's ) ) momentum ) ( ( is ( calculated ( by ( ( multiplying ( ( the mass ) ( of ( the particle ) ) ) ) ( by ( its velocity ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN particle) (POS 's)) (NN momentum)) (VP (VBZ is) (VP (VBN calculated) (PP (IN by) (S (VP (VBG multiplying) (NP (NP (DT the) (NN mass)) (PP (IN of) (NP (DT the) (NN particle)))) (PP (IN by) (NP (PRP$ its) (NN velocity)))))))) (. .)))
The particle's momentum is calculated by multiplying the mass of the particle by its velocity.
(ROOT (S (NP (NNP Momentum)) (VP (MD can) (VP (VB be) (VP (VBN calculated) (PP (IN by) (S (VP (VBG multiplying) (NP (NP (NP (DT an) (NN object) (POS 's)) (NN mass)) (PP (IN in) (NP (NP (NNS kilograms)) (PRN (-LRB- -LRB-) (NP (NN kg)) (-RRB- -RRB-))))) (PP (IN by) (NP (NP (PRP$ its) (NN velocity)) (PP (IN in) (NP (NP (NNS meters)) (PP (IN per) (NP (NP (JJ second)) (PRN (-LRB- -LRB-) (NP (NN m/s)) (-RRB- -RRB-)))))))))))))) (. .)))