Question

A blue train of mass 50 kg moves at 4 m/s toward a green train of 30 kg
initially at rest. The trains collide. After the collision the green train moves with a speed of 3 m/s. What is the final momentum of the blue train?
A. 90 kgm/s
B. 200 kgm/s
C. 110 kgm/s
D. 20 kgm/s

Answer 1

Answer:

C

Explanation:

Use conservation of momentum

Momentum before collision = mv = 50 (4) = 200  kg-m/s

AFTER collision

  30 * 3    + Blue momentum    = 200

    blue momentum = 110   kg-m/s