# Chain of Similar Pendula (Soltion)

1. Jan 19, 2013

### pavelbure9

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.

Last edited: Jan 19, 2013
2. Jan 19, 2013

### Bobbywhy

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

3. Jan 20, 2013

### 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

4. Jan 20, 2013

### pavelbure9

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?

5. Jan 20, 2013

### Bobbywhy

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

6. Jan 20, 2013

### pavelbure9

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.

Sincerely,
Pavelbure9

7. Jan 20, 2013

### Bobbywhy

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