new version of charged particles and walls

[Fu-Kwun Hwang]

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1. Select positive/negative charge and click inside the simulation area to add particles at that
point. (Added particles can be fixed position or freely moving particles).
You can add rectangle wall (provide x,y as top-left corner and width/height (w/h) values)
or circular wall (provide x,y as center and R as radius)
Change Ex or Ey if you need uniform electric field.

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[thmz]

Wonderful simulation. Thanks for sharing it. A few questions and notes.

I tried to make a bunch of circular walls. It seems that I could not make the radius smaller than 20. That was not a big problem.
I ended up making a matrix of 9 adjoining circles. For some reason, several of the circles did not close. Did they need to be away from each other to close?
I also did not figure out how to get it to save a particular setup. That would be nice, especially if I can edit the xml file.
It would be nice if I can assign mass to charges

 
Thanks for all of what you do.
TM

[Fu-Kwun Hwang]

I just modified the above simulation so that you can change mass for each particles. (But the size is not changed.) Click change mass checkbox, than every mass being clicked will be change to the mass in the box. When the checkbox is not checked. The mass being clicked will be displayed in the text field.

You should be able to save the state into memory. If you download it and run it as a java application. You can save the state to a file.

The above simulation was built for arbituary walls.
The walls are consists with segment between adjacent points.
So that the slope of the segment can be used to calculate the collision between particles and walls.
The size of particles are either 4 or 5. It is useless to have circles which is too small to trap particles inside.

If you need a bunchs of circular walls. I believe you have another different situation. May be you want charticles to collide with  small circular walls. That is a different simulation.
You can check out particle model for solid/liquid/gas states or Collision 2D
(However, the above simulations are not for charged particles).

You can download EJS source and modify the code to suit your need! Everything can be changed!

Embed a running copy of this simulation
<applet code='users.ntnu.fkh.chargedParticlesAndWalls2_pkg.chargedParticlesAndWalls2Applet.class' archive='http://www.phy.ntnu.edu.tw/ntnujava/ejsuser/2/ejs_chargedParticlesAndWalls2.jar' name='chargedParticlesAndWalls23714' id='chargedParticlesAndWalls23714' width='760' height='504' mayscript=true><param name='draggable' value='true'></applet>
Embed a running copy link(show simulation in a popuped window)
<a href='http://www.phy.ntnu.edu.tw/ntnujava/msg.php?smfejs=3714' target='smfejs'>Run simulation</a>

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• 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!

[tmzoughi]

Thanks. Actually, I just came back here to post that I ended up doing that, downloading EJS, and modifying the file. One interesting thing I tried was to dump 20 mass 1 negative charges, and 10 mass 100, and charge 2, positive charges. It was neat the way they came together.
I still could not get it to open and save files. I must be missing something. Thanks for all of your help.

[gabrielcox]

Thanks a lot for explaining this topic of physics. This was really difficult for me. I was looking for some information on getacademichelp.com. But you explained it really good.