TRIVIA: a question for physicists

[Cowley]

And a few thousand kilometres away in space

My head hurts!

 

[Dai Corner]

My head hurts!

Fortunately the train has moved by the same amount as our subject, otherwise his head would also hurt, having being propelled violently at the wall!

 

[edwin_m]

My head hurts!

Did you jump high enough to bump it on the ceiling?

 

[MotCO]

Did you jump high enough to bump it on the ceiling?

I am taller than average, so I need to be careful!

 

[Bevan Price]

The answer is about force.

If the train is travelling at a constant velocity (in all 3 spatial dimensions), then regardless of how long you are magically suspended in mid air , then when you land it will be in the same place. This is because there is no net force being applied to you, or the train. (The force the train is exerting is being used to overcome resistance to motion, and st a constant velocity they exactly cancel each other out).

If, however, the train is accelerating or decelerating - again in any of the three spatial dimensions - then you would move during your magical suspension. Probably the best example is if you went around a corner: the train is being ‘accelerated’ to one side, but you would not be. You would then end up, fairly gently, in contact with the inside side of the train, at which point you would then start to experience the same acceleration as the train. You will experience this acceleration every time you go round a corner on a train, particularly if you are standing up and not holding on to a grab pole.
.

And sometimes you hit the side not so gently, as I have seen happen when a Pacer goes through Winwick Jn at 50 mph, and the train conductor was standing up.....