Answer:
Final velocity = 4km/h
Explanation:
This problem involves an inelastic collision involving a rail road diesel engine and a freight car, diesel engine is moving at 5km/h and freight car starts from rest which implies 0km/h, diesel engine weighs 4 times the freight car. Let weight of freight car be P, therefore, weight of diesel engine = 4p
We would use the law of conservation of momentum to solve this problem.
Initial momentum = final momentum
(Diesel engine's initial momentum)+(freight car initial momentum) = combined momentum.
By inputting our data we have
(4p×5km/h)+(P×0km/h) = {(4p+p)}×(final velocity)
20pkm/h = 5p × final velocity
Final velocity = 4km/h
