Question

A railroad car of mass 3.45 x 10⁴ kg is traveling east at 5.50 m/s and collides with a railroad car of mass 4.21 x 10⁴ kg traveling west 1.50 m/s. Find the velocity (in m/s) of the railroad cars that become coupled after the collision. Assume east is the positive direction

Answer 1

Assuming east as the positive x-direction

The initial momentum of the system is

Now, when both the cars get coupled after the collision, the momentum of the system is

Applying conservation of momentum

So, after the collision, the cars move to the east with a velocity of 1.65 m/s.