A 5000-Kg Freight Car Moving at 2 M/s Runs into a 10,000-Kg

Multiple Choice

A 5000-kg freight car moving at 2 m/s runs into a 10,000-kg freight car at rest.They couple upon collision and move away as one body at

A) 2 m/s.
B) 1 m/s.
C) 2/3 m/s.
D) 1/3 m/s.