Jumping a long distance on a train question...

[chris@25]

Assuming the train is not accelerating or decelerating, then you'd jump the same distance in either direction (within the carriage) no matter what speed the train is going.

 

In the same way, you can throw something up in the air whilst sat on a train and it comes back down in the same place, it doesn't fly off toward the back of the train (it _would_ if the train were accelerating hard).

[Tony]

*_ash_* have you considered the effect of the earths rotation, it's movement around the sun and your place on it?

 

Oh yes... air density and pressure within the moving train should make a difference too

[Phanerothyme]

Here's one I often ponder-

 

How should a moving car approach the task of driving on to a moving car transporter- like Knight Rider used to?

 

Depends on whether you have FWD or RWD. I don't know if its possible with permanent 4WD. (nor have I ever tried doing it).

[cgksheff]

Assuming the train is not accelerating or decelerating, then you'd jump the same distance in either direction (within the carriage) no matter what speed the train is going.

 

In the same way, you can throw something up in the air whilst sat on a train and it comes back down in the same place, it doesn't fly off toward the back of the train (it _would_ if the train were accelerating hard).

 

It depends on how accurately you can measure.

[chris@25]

It depends on how accurately you can measure.

 

No it doesn't. In the absence of an accelerating force objects remain at their current velocity.

 

As Tony points out, forget the train, we're all on a platform that's flying through space at several thousand miles per hour, it's called the Earth.

[cgksheff]

Jump out of a plane and say that!

[Cyclone]

Whether you can measure it or not, there will be a difference compared to a similar jump on the ground.

The standing jumper is already travelling at the speed of the train.

When he jumps:

The friction from the train's floor will stop pushing him forward and he will start to decelerate.

(The air enclosed in the carriage will push him forwards slightly and reduce that deceleration.)

 

This deceleration will add to the distance of the jump compared to a jump on the ground.

 

Still probably imeasurable, you would see a movement along the carriage floor if the jumper jumped vertically in the carriage.

 

If the jump was on an open flat-bed wagon, the wind would probably have a greater effect and would actually increase the length of the jump, further.

 

You're over complicating it.

The air inside the train is also travelling at the same speed as the train. Friction on the jumper will be identical to friction outdoors in no wind.

His jump relative to the train floor will cover the same distance as if he were outside as no additional forces act on him compared to his outside jump.

Unless of course the train is accelerating or decelerating, in which case there is no additional force, but his frame of reference is moving relative to him.

[chris@25]

Jump out of a plane and say that!

 

Well then I would experience a decelerating force due to wind resistance. Doesn't apply _inside_ the plane/train, unless it's an open carriage.

[Cyclone]

Jump out of a plane and say that!

 

If you jump out of a plane then there are several forces acting on you.

Gravity.

Resistance from the air in 2 vectors, against your forward speed, and against your downward speed.

If you jump inside a plane there is only gravity and still air resistance, just as if you jump on the ground (although air pressure might make a difference).

[Tony]

(still) air will only resist the direction of travel, not the speed... but you are totally correct to say that "The friction from the train's floor will stop pushing him forward and he will start to decelerate" is nonsense