system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is it, if I am standing on top of a train, and I jump, I will land (or more likely fall) on a further back part of the train. But if I am inside the train and jump, I land on the exact same spot as I was standing on before?
gpt
Because on top of the train youll be subject to loads of wind resistance. And as you jump it'll be pushing you back.

Inside the train there is no resistance acting upon you so you land where you jumped.