If i am running forward in a forward moving train and just at the verge of stopping (the train) i just turn around . so in which direction would i fall and for what reason?

Question

turingtest · Answer

You'd fall on your butt!

Seriously, it is the same as when you hit the brakes in a car; you fly forward. I don't see much difference when you are running in the train in the same direction that it is moving. As the train/car/airplane/whatever vehicle is moving you are moving with it (at a constant speed let's say). If you jump while riding a train, do you suddenly hit the back of the vehicle? Of course not because you are being "thrown" so to speak at the same speed as the train. 

What if the train stops? The brakes act as a force on the train to decelerate it, but you have no such force acting on you, so you will continue to move forward according to Newtons 1st. So no matter which way you are facing/running you will continue moving towards the front of the train until another force acts on you (probably from the impact of a wall or the friction of the floor).

So... if you run forward, turn around suddenly, and the train comes to a screeching halt, you will fall backwards, on your backside (hopefully not on your head).