Falling chimney...

[iacob alex]

Hi !

The quicky quote of the day : "They deem him their worst enemy who tells them the truth"( Plato)...I hope,is it, out of question?!

About the connotations of the up-there word,you can pick them from:

-an encyclopedia book

-on net...my proposal is http://encyclopediadramatica.com/Image:Mysterybot.jpeb

By the way:for your topic,the "falling stick/chimney" problem...it seems to me a "knotty point"...,something alike ,as it was the size of a chopper's blade in the history of aviation.

All the Bests! / Alex

[iacob alex]

....if you type this denomination on net,you can get a plenty of information.

The next step is to relate the "falling chimney " with an "inverted pendulum",but not as a pendulum studied in robotics (a limited and controlled swinging)...this time,the pendulum can fall 180*(a full fall down).

For a physical pendulum,the center of rotation can be somewhere,so that we have a new (and useful for our topic...) image :a first class lever ,with two unequal arms ,free to manifest a full fall down(180*), due to gravity.

The last step is to play,(in some way...),the torque difference on the same side of the pivot.

Why this topic?

Simply,because a pendular fall accelerates more than a vertical free fall.

If we have a difference ,it can be a starting point to think about...

All the best! / Alex

[path_finder]

Dear jacob alex,
Because the MOV video is not standard formatted (speed problems), I made a small animation for the members/guest, allowing a better understanding of what you are referring.
But I did not see how this property can be used. Can you suggest xthing?

[murilo]

''Simply,because a pendular fall accelerates more than a vertical free fall. ''

If this is really true, this is a very and real counter-intuitive stuff. I guess that the acceleration of center of gravity of such pendule is be considered but not the peripheric move.

Nice shot, Path.

Cheers.
Muliro

[getterdone]

Somehow I think that if the ball was heavier, made of lead maybe, he would get a different result.

[iacob alex]

Hi p_f !

Your animation is well suited.

The pendular fall is about ~30 degrees,and we can notice easy the difference.

Now,how about a 180 degrees fall ("full" up-down) ?

I suppose,the difference will be greater,and "helpful" in some way for our topic.

Looking at your pics ("Albums"),I understand that you have a lot of experience (plainly designs and accurate models)so you have a certain level of view.

A "full" (180*) pendular fall (rod-bob),has a certain energy at the final point(bottom position).

This energy can be stored as rotational inertia(an attached flywheel).

A "full" (180*),pendular fall equivalent (first class lever,two equal masses,two unequal arms ),can store gravity energy also.

If the size is reasonable...(something between your models and Aldo Costa's...maybe that of Vandugegs),we can store enough power for the next step:simply,a jump-up on the vertical line,to remake the starting position:arm difference.

As you see,the key word is this "difference".

There is a joking difference,also,between our points of view...

You say:why make simple,when you can make complex?

I say :why make complex,when you can make simple?

Take this as a play on words,plese !

All the best! / Alex

[path_finder]

Dear jacob alex,
My signature is obviously sarcastic and therefore shall be reversed for the common mankind.
Nevertheless there are so many people still doing that way and specially in the psychological matter.

Regarding the suggested use of this concept:
As explained well by murillo the key is the COG in the middle of the ramp.
So far, replacing this COG by a weight is apparently a good idea, but remember Galileo and the Pizza tower: even if you replace the center of the ramp by an elephant, it will not fall quicker.
Thus why increase the weight if the ramp falls at the same speed, including an elephant or not?.
It seems to me that a very light lever (but enough strong for the rigidity reasons) can be sufficient.

Now if this lever of first kind has two opposed weights, how remove the other one on the opposite side? and what to do with the liberated part?

[iacob alex]

Hi p_f !

Firstly,take a look at : http://peswiki.com/index.php/Directory:Gravity_Motors

There,you can read:"...for a rotary device to work,it has to achieve a full 360 rotation,with acceleration between each complete turn".

This is their point of view...

In the same place take a look at "Simple hinged gravity wheels",an animation in the tradition of Johann Bessler.

As I said at "MT13 digest..." topic,the time- serial of this design is Taccola,Leonardo da Vinci,Bessler.

The simplicity is the best expression of knowledge...

You can play a simple test:

-take a long rod/stick/bar with a single and small hinged end .

-this hinged end can perform long- short arm, as a limited 180 degrees rotation,(alike a "knee-joint").

-with this simple variable configuration,you can get a full 360 rotation (even more due to rotational inertia!)...but not a continuous self moving "device" due to gravity.

If you like this plain game,maybe you will arouse inspiration for the next step...

All the best! / Alex

[Fletcher]

The inclined lever always parts company with the weight rested on it but not attached - imagine that the lever was pivoted & that instead of being a continuous medium was in fact made up of a series of masses evenly spaced apart & linked to give a rigid structure - lets says 5 masses starting near the pivot as number 1 to number 5 at the tip, one in the middle & two each side - acceleration due to g acts on this 5 point masses the same so number 1 will attempt to accelerate as will 2,3,4,5 etc - 1 will move downwards in a given time - so, 1 leverages all those beyond it, 2 leverages 3,4,5; 3 leverages 4,& 5; 4 leverages 5.

That means that the lever & the free falling weight part company as pathfinders animation shows - this is a leveraging effect from the mass near the pivot.

[iacob alex]

Hi!

Sorry,but in my opinion,there are two possible turn of events :

-not to read or understand my topics...let's say "MT13 digest..."

-not to play the proposed test up-here .

-test was intended for a "minimal wheel":two opposed arms (first class lever) ,only .

-one arm has a constant length(medium value).

-the second arm has a simple hinged end.

I made the test...this is more important that my words:facts are facts !

All the best! / Alex

[nicbordeaux]

Hi Alex, isn't your quote (signature) " Second step: Arbeit macht frei " a nazi slogan ? Like the sign that they hung outside Auschwitz , and which some very deranged nutcase recently stole ?

[FunWithGravity2]

Would this be a good way to visually explain latency to the newbies:>



Crazy Dave

[iacob alex]

Hi Nick!

About the second step of my signature (Arbeit macht frei/Work make you free),it's nothing more than an old traditional saying in german language...maybe used in other languages,also.

Without work...you know,we go back in history.

If you notice the developments of verbs (...make something...machen...non venditur/don't sell...),you can understand that my intention is to arouse little by litlle ,the interest for the topic of this forum,not as a necessary effect of a money reward.

The real reward is knowledge:like money,the more you have,the more you need.

All the best! / Alex

[iacob alex]

.....at : www.youtube.com/watch?v=Sb62_QesDTw

Formally it's the falling stick lab-demo ,you know from the school.

Practically , it's a sling effect (a>>g) you can meet with a trebuchet ,from the history of the simple machines.

Experimentally , it can be a tentative procedure to discover a "method" to play the "classic puzzle"(launching the short arm into a long arm ) , you know from the history ,also : a gravity powered simple machine , the subject of this forum.

Al_ex

[Kirk]

''Simply,because a pendular fall accelerates more than a vertical free fall. ''

If this is really true, this is a very and real counter-intuitive stuff. I guess that the acceleration of center of gravity of such pendule is be considered but not the peripheric move.

Nice shot, Path.

Cheers.
Muliro

I assure you it is really true. The reason the tip of the board accelerates faster than the free falling object is because it is a machine constructed such that the force from mass not accelerating at 1g (near hinge) is available to further accelerate that which is accelerating at 1g.