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"There is nothing either good or bad, but thinking makes it so." ..."Shakespeare (154-1616, English dramatist and poet) "

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 Author Topic: Magnetic levitation model  (Read 17394 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
pavwell
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 « Embed this message on: May 21, 2010, 12:37:43 pm » posted from:Zilina,Zilina,Slovakia

Hello !
Please, could anyone hepl me with creating Magnetic Levitation of small ball model in EJS ?

Thanks a lot !

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Fu-Kwun Hwang
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 « Embed this message Reply #1 on: May 21, 2010, 05:22:36 pm » posted from:Taipei,T'ai-pei,Taiwan

And the physics to be modeled.
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pavwell
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 « Embed this message Reply #2 on: May 21, 2010, 05:40:44 pm » posted from:Zilina,Zilina,Slovakia

Hello

Parameters and desing is in attachmement
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Fu-Kwun Hwang
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 « Embed this message Reply #3 on: May 21, 2010, 09:58:50 pm » posted from:Taipei,T\'ai-pei,Taiwan

There is one thing I do not understand for the main equation in the above document
$m_k \ddot{x}=\frac{i^2k}{(x-x_0)^2}-m_k g$

What is the meaning of $i$ in the above equatoion?
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pavwell
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 « Embed this message Reply #4 on: May 21, 2010, 10:05:43 pm » posted from:Trencin,Trencin,Slovakia

Sorry !
I forget for this. ,,i,, is constant.
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Fu-Kwun Hwang
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 « Embed this message Reply #5 on: May 22, 2010, 11:56:07 pm » posted from:Taipei,T'ai-pei,Taiwan

Why there are two constant? $i^2 k$, and what is the value of $i$?
L0=0.019 does it mean 1.9cm?
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pavwell
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 « Embed this message Reply #6 on: May 23, 2010, 01:33:28 am » posted from:Trencin,Trencin,Slovakia

L0 is 1.9 cm...

and ,,i, is : electrical power [A] and value is =0.33 Amper
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Fu-Kwun Hwang
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 « Embed this message Reply #7 on: May 23, 2010, 08:30:37 am » posted from:Taipei,T\'ai-pei,Taiwan

Do you mean i is electric current? (instead of power)
Is it a control variable? or it it a constant???

The system seems to be an un-stable equilibrium system. It need some feedback to make it stable, Right?
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pavwell
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 « Embed this message Reply #8 on: May 23, 2010, 12:21:25 pm » posted from:Trencin,Trencin,Slovakia

Yes, it is electric current throught induction. And feedback is needed. In attachment I send you basic scheme.
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Fu-Kwun Hwang
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 « Embed this message Reply #9 on: May 23, 2010, 02:43:22 pm » posted from:Taipei,T'ai-pei,Taiwan

I try to implement a virtual feedback to create the following stable case.
However, you need to change parameters to fit with your own system.

Embed a running copy of this simulation

Embed a running copy link(show simulation in a popuped window)
Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.
Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!
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pavwell
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 « Embed this message Reply #10 on: May 23, 2010, 09:20:12 pm » posted from:Trencin,Trencin,Slovakia

Thanks a lot for your job. But when I try to run in EJS 4.2, it gives me an compilation error. Please, what EJS version i need to use ??
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Fu-Kwun Hwang
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 « Embed this message Reply #11 on: May 23, 2010, 11:35:36 pm » posted from:Taipei,T'ai-pei,Taiwan

The above simulation was generated with EJS4.2
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pavwell
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 « Embed this message Reply #12 on: May 23, 2010, 11:45:01 pm » posted from:Trencin,Trencin,Slovakia

please, could you make this project at EJS 3.4.7 ?? Thanks a lot !!!
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Fu-Kwun Hwang
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 « Embed this message Reply #13 on: May 24, 2010, 08:23:39 am » posted from:Taipei,T\'ai-pei,Taiwan

You should be able to copy the code to 3.47 if you open two version of EJS
Just define  the same variables, copy the same initialization/evolution/... and add similar GUI elements.
The only difference is that there is no two states button in EJS 3.47
So the play/pause button need to be separate as two buttons.

And you need to adjust the code to fit with your system.

And you should be able to finish it by yourself! You need to at least try it!
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pavwell
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 « Embed this message Reply #14 on: May 25, 2010, 03:29:02 am » posted from:Trencin,Trencin,Slovakia

When i try to run this XML file under Ejs 4.2 , system gives me an error ! Compilation error. When i look over the code i found one red line ay=calF(....). Dont you konw what could be a problem ??
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Fu-Kwun Hwang
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 « Embed this message Reply #15 on: May 25, 2010, 07:57:39 am » posted from:Taipei,T\'ai-pei,Taiwan

I also use EJS 4.2 However, I did not find any error. So I do not know how to help.

The ay was defined as double with initial value "calF(y,vy)/m-g"
It can be re-assigned to 0. without affect the code.

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"There is nothing either good or bad, but thinking makes it so." ..."Shakespeare (154-1616, English dramatist and poet) "