A 5000-kg freight car crashes into a 10,000-kg freight car at ...

[armygirl]

A 5000-kg freight car crashes into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg freight car?
 
  A) 4 m/s
  B) 5 m/s
  C) 6 m/s
  D) 8 m/s
  E) none of the above

Question 2

Two identical freight cars roll without friction towards each other on a level track. One car rolls at 2 m/s and the other car rolls at 1 m/s. After the cars collide, they couple and roll together with a speed of
 
  A) 0.5 m/s.
  B) 0.33 m/s.
  C) 0.67 m/s.
  D) 1.0 m/s.
  E) none of the above

[Laurenleakan]

Answer to Question 1

Answer: C

Answer to Question 2

Answer: A

[armygirl]

Gracias!

[Animal_Goddess]

Excellent