If you were standing on a train travelling at high speed

[Norm]

I still think this is true though, isn't it? except the drag bit.

No.

Why would you slow down?

 

[jimboalee]

If you was on a train from Kings Cross to Edinburgh, you'd land slightly westbound. If you were on a train from Edinburgh to King's cross, you'd land slightly westbound.

 

[JtB]

Is there something about cycling that makes cyclists ponder such profound and important questions about the universe in which we live...














and then spout so much twaddle

 

[Norm]

and then spout so much twaddle

Indeed, given that the answer was written in the first reply.

However, you were the one who suggested that a fly could stop a speeding train.

 

[Dilbert]

No.

Why would you slow down?

Because you are subjected to the same drag as you were but without the opposing propulsion which was keeping you moving at a constant speed (Newtons First Law if memory serves).

If you were lying down, wearing a lycra body suit (sorry if you are having your lunch) and managed to jump up in that position your drag would be less than if you were standing up wearing a ballgown, so you would not go as far back for a given height. We are talking about very small distances here but theoretically you would move back by some distance. The faster you are going the more important the drag becomes, so if the train was moving slowly this would not have such an effect.

As has been said already all this assumes you are on top of the train not inside it where you would not be subject to drag and your momentum would carry you at the same speed as the train.

And as Jimboalee says there is also the effect of the earths rotation (Coriolis Effect) to consider

 

[Norm]

Ah, I see, you are literally standing on top of the train whilst I'm snug, warm and dry helping myself to a coffee inside it.

In that case, you are correct, if a little windswept and WATCH OUT FOR THAT BRIDGE!

 

[jimboalee]

When you jump up in a speeding train, at the top of your jump you will be 'weightless', so in this situation, you will be attracted by the gravity of the nearest large object.

That of course will be the Earth, but there might be another sizable object such as the 6'7" man standing next to you.

He, having mass, will possess some gravity and you will momentarily be attracted to him.

If he is coincidentally westward of you, the rotation of the Earth will be added to your movement and your landing spot will be on the same piece of carpet as the guy's shoe.

When you land, he will give a loud shout and then you will find yourself travelling toward the window with a sharp pain in your jaw.

Moral - don't jump in a crowded train. Unless you can accurately vector your launch.

 

[Fnaar]

He, having mass, will possess some gravity and you will momentarily be attracted to him.

Would there be enough time, do you think, to blow him a kiss, or perhaps flutter ones eyelids a bit?

 

[jimboalee]

Would there be enough time, do you think, to blow him a kiss, or perhaps flutter ones eyelids a bit?

Probably not, but don't, whatever you do, grasp on to anything to break your fall.

 

[Panter]

So gravity would provide the drag and you would land in a different spot

 

[Rhythm Thief]

Will you lot stop jumping up and down? This is the quiet carriage and I'm trying to read my book.

 

[Norm]

So gravity would provide the drag and you would land in a different spot

**In order to avoid further stress, Norm steps away from the keyboard**

 

[Panter]

No need to stress, I'm right

And a few more for luck

 

[Tollers]

OK....it's late here and im drunk....but i loathe jimbo. he has the remarkable talent of talking crap and making it sound authorative. I talk the truth and it sounds like balls. Grrrrrrr Jimbo!

 

[Yellow Fang]

Newton's first law:

"Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by the forces impressed on it."

The train is moving at X mpg, you're moving along at X mph, the air in the carriage is moving at X mph, so there's no friction. Therefore you're going to land exactly where you were on the train.