system
Given the following post, respond as if you're commenting on Reddit:
human
A bird traveling 60mph enters a train car traveling 60mph parrallel to it. What happens to the bird?

Lets say it enters the train car through a small window on the side of the car. What happens to the bird upon entering? Does it fly forward and hit the front of the car? Does it fly backward and hit the back? Or does it simply stay in the same position, flying in the middle of the car?
gpt
If the bird glides in through the window, it is liable to fall down to the floor of the car. It has been using 60 mph relative wind for lift, and that suddenly drops to zero. Also, it has been using its wings (or descent, if that is how it keeps its speed outside) to power it into a 60 mph relative headwind. The headwind suddenly drops to zero when the bird enters the car. It if keeps flapping its wings (or descending) when it is inside the car, it will hit the front of the car. If it just glides horizontally into the car, it will only have to contend with the change in lift and deceleration as it enters the air in the car.