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

C

Step-by-step 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