help with a physics question?

Question

A railroad freight car weighing 285 kN and traveling at 1.50 m/s overtakes one weighing 214 kN and traveling at 0.912 m/s in the same direction. The cars couple together.
Find the speed of the cars after collision.

_________m/s

Answer 1

Concervation of momentum
m1V1 + m2V2= (m1+ m2)V

V= (m1V1 + m2V2)/(m1+m2)
V= (1/g)(w1V1 + w2V2)/(w1+w2)(1/g)
V= (w1V1 + w2V2)/(w1+w2)

V= (285E+3x1.50 +214E+3 x 0.912)/(285E+3 +214E+3 )=
V=1.25 m/s