A 1000-Kg Car Is Traveling North at 20

Multiple Choice

A 1000-kg car is traveling north at 20.0 m/s. A 1500-kg car is traveling north at 36.0 m/s. The 1500-kg collides with the rear of the 1000-kg car and they lock together. Ignoring external forces acting during the collision, what is the velocity of the cars immediately after the collision?

A) 56.0 m/s north
B) 29.6 m/s north
C) 13.6 m/s south
D) 8.00 m/s south
E) 28.0 m/s north