0Physics is not only a subject it is an observation. So if someone wants to learn physics first thing he needs to learn is just how to observe things. Just take an example of a guy who is sitting inside a train, and you are an observer who is observing that guy from the bench which is situated on the platform so what you say that guy is moving, or he is in rest. So your answer is just that he is running with the exact velocity from which the train is moving. Now assume that you are sitting inside the train then what you will say that guy in rest because you are also running with the same velocity from which your observer moves, so that's why I told physics need observation.
