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Author: Subject: Monday puzzle - which way will the little cart go?
craig1410

posted on 1/8/11 at 05:53 PM Reply With Quote
quote:
Originally posted by russbost
"This in turn makes the large wheel rotate counter clockwise" Ok, so you are pushing to the right with the ruler, but the large wheel is rotating counter clockwise - please explain how this could be possible without slippage being present between the ruler & the large wheel???


It is possible without slippage only if the cart goes faster than the ruler. As per the mathematical proof, the velocity of the cart is ruler velocity + angular velocity of big wheel * radius of big wheel.

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JoelP

posted on 1/8/11 at 05:56 PM Reply With Quote
lol, i love a nice argument.

My input, apart from agreeing with craig (for once, since we're not talking f1 ), is that all that counts is that the ruler cannot slip on the big bobbin and the table cannot slip relative to the little bobbins. Then the cart can go in any damned direction it likes, irrespective of which way the ruler goes, so long as nothing has to slip. It is entirely down to the gearing and the fact that once the cart moves relative to the table, it also moves relative to the ruler in additon to the existing motion of the ruler (relative to the table). This thus adds a new dimension to how the cart moves relative to the table, and both aspects must be worked out simultaneously to decide how it moves overall. And this is why its difficult to predict before watching the video, because it appears that it should move left - but this left motion would have an effect on the big bobbin that causes the cart to move right anyway.



Skip this bit if you want...

if the ruler moves 2cms to the right, the big bobbin turns 2cms round, causing the little centres to go 2 cms the other way, which equates to maybe 3cms at the rim. So the cart moves 3cms left, but that 3cms left rubs the ruler on the bobbin, which causes the small rim to turn 4.5cms back towards the right, or 1.5cms further right than it started. Obviously it doesnt move left then right because nature solves both equations at once. That 1.5cms would have an additional effect too...



A similar concept is how a large boat with turbines instead of sails, can go directly up wind, even though that seems impossible.

[Edited on 1/8/11 by JoelP]






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Liam

posted on 1/8/11 at 05:56 PM Reply With Quote
quote:
Originally posted by russbost
"This in turn makes the large wheel rotate counter clockwise" Ok, so you are pushing to the right with the ruler, but the large wheel is rotating counter clockwise - please explain how this could be possible without slippage being present between the ruler & the large wheel???


Because it's moving to the right faster than the ruler, as you can see, hence it rotates counter-clockwise. This whole thing would work equally well, and perhaps be clearer, if the wheels were all toothed cogs and the ruler was a toothed rack.

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JoelP

posted on 1/8/11 at 05:59 PM Reply With Quote
and it is alarming nonsense, the suggestion that the ruler is being pulled left but moves right.






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craig1410

posted on 1/8/11 at 06:02 PM Reply With Quote
What we should all be thinking is how can we make use of this phenomenon to make our Locosts faster????

Imagine what you could do if you had a 1/4 mile long ruler attached to an engine which was on the ground next to the drag strip start line. You would then have a super light car (no engine) with a huge wheel sticking out the sunroof and touching the ruler. Then you just need a remote control between your throttle pedal and the engine beside the track!

2 second 1/4 mile here we come..............oh yeah, you might need a parachute too...splat! Too late!


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Ninehigh

posted on 1/8/11 at 06:53 PM Reply With Quote
quote:
Originally posted by craig1410
Here's a mathematical explanation:


WITCHCRAFT!!






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splitrivet

posted on 1/8/11 at 06:58 PM Reply With Quote
Only on Locost builders, you see something with your very eyes and still theres 30 odd posts disagreeing with it.
Sheesh.
Still trying to work out how the teddies could answer questions.
Cheers,
Bob





I used to be a Werewolf but I'm alright nowwoooooooooooooo

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tompat3463

posted on 1/8/11 at 07:20 PM Reply With Quote
opp direction as ruler and same speed as the smallers bobbins are just acting as Idler gears.. 1:1 ratio !?!?!?!?
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Ninehigh

posted on 1/8/11 at 07:22 PM Reply With Quote
quote:
Originally posted by splitrivet
Still trying to work out how the teddies could answer questions.
Cheers,
Bob


WITCHCRAFT!!








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MikeRJ

posted on 1/8/11 at 07:33 PM Reply With Quote
quote:
Originally posted by splitrivet
Only on Locost builders, you see something with your very eyes and still theres 30 odd posts disagreeing with it.
Sheesh.



I think most people haven't grasped the idea (or at least the importance of the idea) that the bobbins have two different diameters, the part that touches the table and the part that touches the big centre wheel. This is absolutely fundamental to the operation of this gadget, if the bobbins were simple cylinders it would not work at all.

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tompat3463

posted on 1/8/11 at 07:40 PM Reply With Quote
if u disregard the the ruler being pushed or pulled and in fact the ruler could somehow balance itself on the large wheel by itself.

then push the white connecting plate things then the mechanics, ratios, motions would all be the same.

it doesn;t matter if the ruler is being pulled or pushed...the idea is the same.

u gys should know better as its exactly the same as say a cam belt with anchilary wheel on it..

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craig1410

posted on 1/8/11 at 07:40 PM Reply With Quote
quote:
Originally posted by MikeRJ
quote:
Originally posted by splitrivet
Only on Locost builders, you see something with your very eyes and still theres 30 odd posts disagreeing with it.
Sheesh.



I think most people haven't grasped the idea (or at least the importance of the idea) that the bobbins have two different diameters, the part that touches the table and the part that touches the big centre wheel. This is absolutely fundamental to the operation of this gadget, if the bobbins were simple cylinders it would not work at all.


Exactly!

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