Eli5: why when I’m standing on a moving train and I jump, the train doesn’t move around me?

Question

Eli5: why when I’m standing on a moving train and I jump, the train doesn’t move around me?

In: Physics

Answer 1

You push upwards when jumping, so you do not change your horizontal speed when you jump. It remains the same as the speed of train. If, however, the train accelerated or slowed down exactly at the moment you jump, then it will move around you, forwards or backwards.