Post, Freight and Carriers

A train and freight car crash and physics is supposed to matter?

A railroad diesel engine weighs four times as much as a freight car. If the engine travels at 5 km/h into the freight car at rest, how fast do the two travel after they couple?

Public Comments

1. Pi = 4*5 = 20 Pf = 20 = (4+1)*V → V = 4 km/h