A 45,000 kg train car moves at 10 m/s toward a 17,000 kg train car at rest. After the two cars collide, they couple together and move along the track in the same direction.

Question

What is the velocity of the cars after the inelastic collision?

Answer 1

m = 17,000 kg

M = 45,000 kg

v = 10 m/s

u = speed after the inelastic collision

Conservation of linear momentum requires that

Mv = (m + M)u

u = [M/(m + M)]v

You know M, m, and v. Plug in the numbers and finish from here.