Jumping a long distance on a train question...

Ok, most of my thread questions are bizarre, (tame compared to what really goes on in my head:hihi:).

But this one I want answering. Thick or not.....

Ok if you ran and jumped on a travelling train (jumping in the opposite direction to the train), you would think that your distance jumped would be greater because the train is travelling in the other direction underneath you.

Of course, you are travelling at the same speed as the train, so Mr or Mrs average wouldn't jump any further. (or am I wrong?)

But watching a long jumper and seeing how long they stay in the air, would the jumpers travelling speed be reduced in that time, and they would therefore travel a further distance?

no wonder I'm single:hihi:I don't half open myself up to silly posts.

'Distance' being that measured along the carriage floor?

Good question.... don't know the answer, like, but very good....

'Distance' being that measured along the carriage floor?

Yep.

I'm not recommending anyone try on the 0727 to London.

Good question.... don't know the answer, like, but very good....

I made the conscious effort to ask it while Bay-Sil is offline.

What about if, at the moment person A is takes off on their jump along the train, person B jumps in front of the train, causing an emergency stop. While in the air with full momentum in one direction, plus rapid deceleration in the other direction, could person A conceivably land further back than he started?

This is all reminding me of Newtonian principles in my maths A level class. The OP should be recited in Mr Cathcart's broad Ulster tones while scrawling chalk equations all over the classroom wall and door.

Before anyone says it, person B is not me.

Relative to the train, the jumper can only jump as far as he can jump. If Carl Lewis takes a running long jump and takes off at the entrance to the carraige, he won't land more than 8.9 metres inside the carriage.

Of course, relative to the ground outside, all sorts of weird and wonderful things can happen. If he's taking his run-up in the opposite direction to that in which the train is going, his take-off point might be level with a milepost, but his landing point, 8.9 metres further down the train, might easily be fifty yards past the milepost in the opposite direction.

Ok, most of my thread questions are bizarre, (tame compared to what really goes on in my head:hihi:).

But this one I want answering. Thick or not.....

 

Ok if you ran and jumped on a travelling train (jumping in the opposite direction to the train), you would think that your distance jumped would be greater because the train is travelling in the other direction underneath you.

 

Of course, you are travelling at the same speed as the train, so Mr or Mrs average wouldn't jump any further. (or am I wrong?)

 

But watching a long jumper and seeing how long they stay in the air, would the jumpers travelling speed be reduced in that time, and they would therefore travel a further distance?

 

no wonder I'm single:hihi:I don't half open myself up to silly posts.

Ash, mate, this is reasonably simple mechanics, but I can't make head nor tail of your example!

Friction is a major factor here, I think.

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.

When he jumps:

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

The friction from the train's floor isn't pushing him forward in the first place. He carries the same velocity as everyone and everything else on the train.

On the other hand, if he took his jump while the train were accelerating, you'd have a good point. I think we're all assuming at train moving at constant speed.