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 speed of the blue train?

Answer 1

Explaination :

Momentum = mass x speed

p = (30 kg) (3 m/s)

p = 90 kg m/s