Jumping a long distance on a train question...

[medusa]

You really were bored last night, weren't you Ash?

 

I have no idea BTW.

[cgksheff]

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.

 

 

He has only reached that velocity by virtue of the friction between his shoes and the floor and possibly holding on.

 

Without that friction, he would be flat against the door at the back of the train.

 

The train is 'pushing' him.

When he jumps up vertically, the train no longer pushes him and he will start to slow down.

(the air in the carriage will push him a little as well)

[Heyesey]

He has only reached that velocity by virtue of the friction between his shoes and the floor and possibly holding on.

 

Yes, while the train is accelerating; but once the train (and he) reach a constant speed, this no longer applies.

[Cynic]

I have had the same though about once a month for the last 20 years! It really bothers me! I usually come to some conclusion and then think about a fly flying about the carriage and confuse myself even further. As the fly clearly isn't flapping it's little wings fast enough to travel the same speed as the train. So if you jump you are in the same position as the fly, so should jump no further relative to the train than you would on the ground.

[Tony]

*_ash_*, didn't you attend school?

[*_ash_*]

*_ash_*, didn't you attend school?

Funny that you should say that. My mate has just come round for a cup of tea, and it's all his fault that I didn't go to school much.... more important things like dissecting ZX Spectrums to see what colours we could achieve on screen, and mapping Jet Set Willy 2 on stolen graph paper from school seemed much more important.

 

Looks like he paid more attention though. He says that if a long jumper jumped 5 metres on land. Then did exactly the same jump on a train at a constant speed, he would also jump 5 metres, whichever way the train is travelling in.

 

I'm getting a headache.

 

*puts kettle on*

[theripsaw]

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?

[*_ash_*]

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.

I think I worded this bit badly...

would the jumpers traveling speed be reduced in that time, and they would therefore travel a further distance?

This is more what I was getting at. (highlighting the bold bits)

The standing jumper is already traveling 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.

The difference covered by a jumper would be immeasurable I guess.

 

The reason I used a long jumper as an example, is that I can't think of anyone who can stay in the air as long. (without resorting to using characters from 'Heros'

[*_ash_*]

I have had the same though about once a month for the last 20 years! It really bothers me! I usually come to some conclusion and then think about a fly flying about the carriage and confuse myself even further. As the fly clearly isn't flapping it's little wings fast enough to travel the same speed as the train. So if you jump you are in the same position as the fly, so should jump no further relative to the train than you would on the ground.

At least I'm not alone with such thoughts.:hihi:

[whitehorses]

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.

 

This makes my head hurt,just forget all about it and catch the next train!!I also though you meant 'Jump the train' IE not pay your fare.I remember these kinda problems from school and I just switched off and stared through the window, no hope of me working this out:huh: