A railroad diesel engine weighs four times as much as a freight car. If the diesel engine coasts at 5 km/h into a freight car initially at rest, what is the speed of the coupled engine and car?

20

Explanation:

cause boi

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