eli5: At constant speed and no vision, are you supposed to be able to tell if you are travelling forward or backwards? How?

Question

Was on the train and it was pitch black outside. Thought I was sitting facing the direction of travel but turned out I wasn’t.

Even when I felt the acceleration/decelerating, I didn’t know which it was.

In: 16

Answer 1

No, at constant speed you aren’t supposed to feel any motion at all. Only acceleration (change of speed) should be felt.

For example, we know the earth rotates, but we don’t feel its rotation.