Chain of Similar Pendula (Soltion)

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Discussion Overview

The discussion revolves around the mechanics of a chain of similar pendula connected by light strings, focusing on the application of a stable and strong force to initiate and maintain their motion. Participants explore various methods to achieve consistent force application for experimental purposes, particularly in the context of testing the sine-Gordon equation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Experimental/applied

Main Points Raised

  • pavelbure9 describes a setup of pendula that require a significant force to initiate motion, seeking alternatives to manual force application.
  • Bobbywhy shares personal experience with similar pendula and questions the need for a stable force, suggesting that manual activation can be effective.
  • pavelbure9 clarifies that their experiments require precise and repeatable force application, which manual methods cannot provide.
  • Bobbywhy proposes using an electromechanical solenoid to apply a consistent force, detailing how it could be implemented in the experiment.
  • pavelbure9 expresses gratitude for the suggestion and indicates plans to experiment with different pendulum sizes.
  • Bobbywhy encourages sharing results from the experiments with the community.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and effectiveness of manual versus mechanical force application. While some suggest that manual activation is sufficient, others emphasize the need for a more controlled method, indicating that the discussion remains unresolved regarding the best approach.

Contextual Notes

The discussion highlights the need for consistent force application in experiments, but does not resolve the specifics of how to achieve this effectively across different pendulum sizes.

pavelbure9
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I have a chain of similar pendula which is mounted equidistantly along a horizontal axis with adjacent pendula being connected with light strings. Each pendulum can rotate within
the axis but can not move sideways.

at the page http://btakashi.jp/archives/935 scroll to the bottom of the page and there is a pdf file to look at the image

Some big force is needed aside from the motor to have the pendula spin connected to each other, and I cannot use my hand because it is inaccurate.

So.. what kind of forces can be used as the "some big force"?
Also, how should I apply this "some big force" to the pendula? Again, I need a stable and strong power source.
 
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pavelbure9, Welcome to Physics Forums!

I have been experimenting with and studying these pendula for a long time. We have a large working system in our museum.

Sorry, but I cannot get to that http site to see the image. The link does not open for me. Can you please check it to be sure it works for you? Thanks. Then, possibly others here can give you some tips/advice.

Cheers,
Bobbywhy
 
pavelbure9, Thank you, the link above works now; I've seen the video!

That array of pendula looks much like the one in our Museum. We also activate ours by "hand". I don't know what you mean by that is "innacurate". It seems to demonstrate the sine-Gordon kink soliton very well. What is your objective?

Cheers,
Bobbywhy
 
Oh our one only looks like the one in video. In fact, it's much smaller( 50 cm long,10 cm pendula). We are also conducting experiments testing sine-gordon equation. But we are testing the variables of it in ceteris paribusconditions to get exact data. To do this, we need exactly same amount of force each time doing experiments. Obviously,our body cann't do it. Do you have in mind any ways to apply force to pendula other than using human body?
 
Ceteris paribus conditions to stimulate the pendula motion may be accomplished using an electromechanical solenoid. Position one where the shaft pushes against one pendulum. Energise the solenoid with the same voltage every time, the applied force would then be the same every time.

For a description, see:
http://en.wikipedia.org/wiki/Solenoid

You could buy one here for around TWO DOLLARS:
http://www.allelectronics.com/make-a-store/category/575/Solenoids/1.html

Cheers,
Bobbywhy
 
Thanks a lot.
Me and my friend were trying pendulums with different sizes, from very small to big.
Thanks to you, I think we can get through this experiment.
Hope you enjoy your day.Pavelbure9
 
When you do your experiment you might post the results and or video here on Physics
Forums. Members and Visitors will be interested in your results. This is a place to share science.

Cheers,
Bobbywhy
 

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