NTNUJAVA Virtual Physics Laboratory
Enjoy the fun of physics with simulations!
Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

JDK1.0.2 simulations (1996-2001) => Dynamics => Topic started by: Fu-Kwun Hwang on January 29, 2004, 05:22:37 pm



Title: Kepler Motion
Post by: Fu-Kwun Hwang on January 29, 2004, 05:22:37 pm
During the last quarter of the 16 century, the Danish nobleman Tycho Brahe provide careful observation of the planets over an extended period of time (20 years).
He hoped to use his data to verify his own model of the solar system, in which the sun orbited th earth and all other planets orbited the sun.
At Brahes death at 1601, his assistant Johannes Kepler inherited the data that Brahes had accumulated.
Kepler spend some 20 years analyzing these data, looking for mathematical regularities.
He came to the conclusion that the ideal of circular orbits should be discarded and replaced with elliptical orbits.
Kepler summerized his laborious study of planetary motion with the following three laws:
1. The planets move in elliptical orbits with the sun at one focus.
 2. A line from the sun to any planets sweeps out equal areas in equal time.
 3. The square of a planet's period is proportional to the cube of the planet's mean distance from the sun.
This java applet let you play with Kepler's laws and learn more physics insight.

Study ,
 
when initial conditions changed




    The red circle at the center of the screen represent the sun.
     The moving yellow circle is the planet.
     The initial condition is represented by the blue arrow.
     The planet start from the starting point of the blue arrow,
      and its initial velocoty is proportional to the length of the arrow.


    You can drag the blue arrow to change its initial condition in three different modes:
     1. fixed kinetic energy
     2. fixed angular momentum
     3. arbitrary
    Find out the relation between shape and size of the trajectory with the above parameters.

Right click the mouse button to suspend the animation. Click it again to resume.
What if you click it with the left mouse button? Find out by yourself.
Use reset button to clear the screen. (Try to compare different trajectorys before press it!)
You can select four different mode to play with it.
For the energy mode or while you drag the mouse button:
    The lower green curve is the potential energy : U(r)=-GMm/r
     another one is the effective potential energy Ueff(r)=-GMm/r + L2/(2mr2)


The following is a flash movie which shows you what you can do with the above simulation.



Two horizontal red lines show the total energy of the particle.  (watch the small moving dots! )
The period of the particle motion is also shown in real time unit.

[youtube=GcKiG-CuvtA]


Title: topic9
Post by: on January 30, 2004, 11:23:48 am
Subject: Re: thanks!
Date:    Sat, 05 Dec 1998 18:52:08 -0500
From:    dgoodwin <dgoodwin@1st.net>
To:      Fu-Kwun Hwang <hwang@phy03.phy.ntnu.edu.tw>
Thanks so much for taking the time to send me the http for circular motion and
ang. mo.  I really appreciate it.  It's great stuff.  Bye for now.  Dave G.

Fu-Kwun Hwang wrote:

> I am really sorry for the late reply. This message was misplaced.
> There are two java applets related to the angular
> Kepler motion:  http://www.phy.ntnu.edu.tw/java/Kepker/Kepler.html
> and circular motion
> http://www.phy.ntnu.edu.tw/java/circularMotion/circular3D_e.html
>
> dgoodwin wrote:
>
> > Do you have any applets on angular momentum??
> >
> > Fu-Kwun Hwang wrote:
> >
> > > dgoodwin wrote:
> > >
> > > > We were reviewing vector addition this evening at a study session.
> > > > Someone asked about help from the internet, so we searched and happened
> > > > to find your page.  There were a few "ah-ha's" when the program showed
> > > > the parallelogram method for adding vectors so clearly.  Thanks.
> > >
> > > I am very happy to know that you are enjoy the java applets. Any
> > > suggestions you might have about my java applets will be highly
> > > appreciated! Or , if you would like to have java applet one any topic
> > > related to physics,
> > > Just send me a note! Enjoy the virtual physics laboratory!


Title: topic9
Post by: on January 30, 2004, 12:44:33 pm
Subject: Very Nice Applet
Date:  Sun, 01 Aug 1999 18:34:25 -0500
From: Greg Hecht <ghecht@ix.netcom.com>
To: hwang@phy03.phy.ntnu.edu.tw
Very interesting and educational java applet, sir.  My compliments.

I am not an astronomer but studied Kepler's laws years ago.  Your applet
is the best tool I have ever seen to allow one to grasp the concepts.
Thank you for creating and sharing it.

Cheers,

Greg Hecht, MCSE
The Riverpoint Group, Ltd.
Kansas City


Title: topic9
Post by: on January 30, 2004, 12:49:23 pm
Subject: kepler motion applet
Date: Thu, 23 Sep 1999 06:00:13 -0700 (PDT)
From: lee taishen <leetaishen@yahoo.com>
To: hwang@phy03.phy.ntnu.edu.tw
Dear Mr. Hwang,

Referring to the kepler motion applet in the below
add.
http://www.phy.ntnu.edu.tw/java/Kepler/Kepler.html
I find it very interesting. However, I have some
difficulties when using the applet.

1. For second kepler law, the area of the shaded area
and non-shaded area should be the same. However, there
is no data showing what the area is.

2. for third kepler law, i observed that there is no
indication of the period of the planet. There is this
T value indicated in the applet but it is not the
period. i would appreciate if you can explain what the
T value is.

thank you.

best regards
leetaishen


Title: topic9
Post by: shiva on September 19, 2005, 11:07:53 pm
Dear Friend,
I am looking for applets related to rotational motion, angular momentum, torque and kepler's laws to teach my students.

Can anybody help me?

with thanks,
Shiva: s_iva20290@yahoo.co.in


Title: topic9
Post by: Fu-Kwun Hwang on September 21, 2005, 07:16:02 am
Please write down in more detail what kind of simulation you really want?  (What kind of presentation/GUI view/...)


Title: Source Code
Post by: wuenscher on June 22, 2006, 03:19:32 pm
Hallo,

you have written a nice applet. :)

I want to start writing physical applets. Could you send me some source code? It would help me to understand applet programming. :!:

At first I want to write an applet about the Kepler problem perhabs with an r^-a potential, so your applet would be a good start for me.

Thanks.

michael


Title: topic9
Post by: Fu-Kwun Hwang on June 22, 2006, 03:34:51 pm
You should have received source code in your email box now.


Title: Re: topic9
Post by: Prihatmoko on March 03, 2007, 12:53:30 pm
Hello Mr Hwang

I do believe that it is more beatiful if this applet give some addition by giving user a chance to change the eccentricity of ellips, so people like me can also watch how much different between the rotation of earth and pluto...even it is a planet no more 
;D

Thanks....


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on March 04, 2007, 09:50:26 am
 ;D You can do what you want with that applet. ::)
If you did not change the default setting in the applet: Fix kinetic energy when change initial conditions.
You will get planet motion with the same eccentricity of ellips.

However, if you change it to "fix angular momentum", then you will get  planet motion with different eccentricity of ellips.  :-*

That is why I add the following sentences in the page:
Quote
You can drag the blue arrow to change its initial condition in three different modes:
 1. fixed kinetic energy
 2. fixed angular momentum
 3. arbitrary
Find out the relation between shape and size of the trajectory with the above parameters.

I hope students can really play with it and discover the difference , and figure out some relations!  ;)


Title: Re: Kepler Motion
Post by: tropical72 on April 23, 2007, 12:57:10 pm
Dear Mr.Hwang

I'm a student majoring in CS. I'm preparing a code of Kepler's law.

Luckly I found your homepage and saw the simulation. That's really cool and great.

I tried your simulation for a long time and became curious how it was implemented.

If it's possible, could you send me the source code of the simulation?

That's would be greatly helpful to know the Kepler's Law and the Java programming both.



Thanks in advance

Hyuck


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on April 23, 2007, 03:39:08 pm
I just sent you the source code. You should have received it now.


Title: Re: Kepler Motion
Post by: shiksha12 on October 01, 2007, 06:19:17 am
 :)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on October 06, 2007, 05:51:11 pm
I do not know how to help because you did not say what kind of help you need!


Title: Re: Kepler Motion
Post by: shiksha12 on October 07, 2007, 05:11:18 am
 :)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on October 07, 2007, 12:02:30 pm
Could you at least explain what you want to create? What kind of simulation? What you want to show in the simulation?
Do you have the formula now? What are the form of your formula? What is your model for the simulation?
There are so many information which you did not provide.
I can not read your mind.

I think you also need to learn: How to ask a question effectively?  How to explain your problem?
If I do not have a very clear picture of what you really want to do. There is no way I can help.


Title: Re: Kepler Motion
Post by: shiksha12 on October 09, 2007, 07:09:00 am
 :)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on October 10, 2007, 10:57:43 am
Kepler is a simplify model to understand the motion of planets. If you want to know the detail of the trajectory,
yes. you need Newton's law.
You can check out motion of Moon, Earth relative to the Sun (http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=547.msg1808#msg1808), which simulate gravitation forces between 3 objects. If you have more planets, it can be done with simulation easily. But you will have to set up the right initial conditions, otherwise, the system might not form a solar system if the total energy is not in the correct range.


Title: Re: Kepler Motion
Post by: gk8 on November 08, 2007, 04:53:11 pm
Hello,
Can you please send me source code for Kepler motion? Nice applet. Thx


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on November 08, 2007, 10:02:59 pm
You should have received the source code now.


Title: Re: Kepler Motion
Post by: tharses on November 16, 2007, 03:49:19 pm
Hello

it would be nice if you could send me the source code of the kepler s motion applet !!

thanks
tharses(tharses@hotmail.com)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on November 16, 2007, 08:44:58 pm
You should have received the source code now.


Title: Re: Kepler Motion
Post by: Azmodaii on January 10, 2008, 09:25:46 pm
Hello, your applet is extremely helpful to me and I was wondering if i could also possibly get the sourcecode for this applet as well... my email is azmodaii@gmail.com.


thank you in advance :)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on January 10, 2008, 10:58:09 pm
You should have received the source code now.


Title: Re: Kepler Motion
Post by: vladi on January 11, 2008, 02:48:37 pm
Dear Mr.Hwang, can you please send me source code for Kepler motion? thanks


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on January 11, 2008, 09:26:20 pm
You should have received it now.


Title: Re: Kepler Motion
Post by: quinteroc on February 14, 2008, 04:27:16 am
Hi I am a student of physics from Venezuela...I really like your applet
Could you send me the source please?? I would appreciate it...


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on February 14, 2008, 10:32:12 am
I just add the source code to the zip file for download because there are so many request for source code.
 Please download it again(click get applet file for offline use button ) and you will find the source code.


Title: Re: Kepler Motion
Post by: aesha on February 15, 2008, 03:40:39 pm
thank u so much for your help. i just got what i wanted !!! Thanks for adding source code file in zip ile.!! :)


Title: Re: Kepler Motion
Post by: aesha on February 15, 2008, 03:44:04 pm
thank u so much for your help. i just got what i wanted !!!!! :)


Title: Re: Kepler Motion
Post by: Daniele on May 30, 2008, 08:00:49 pm
Hi,
I found your applet very usefull and clear. I am an astronautical engineer and I am coping for the first time with Java. I used to program in MATLAB/SIMULINK environment, therefore the point of view is quite different because of the Java Object Orientation. I would like to ask to the author of the applet some additional detail about the integration of the equations of motion:

1. What kind of numerical integrator did you use (RK4, Euler,...)?
2. Is it possible to integrate non linear ODE of the second order (i.e. the equations of motion for the restricted three body problem) or it is necessary to transform every equation of the second order in two equations of the first order?
3.I went through the source code of the applet, but it is quite confusing for a new Java user; is it possible to point out the section of the code where the integration is performed?

I do apologize if these questions may seem elementary, but the approach needed to program in Java is completely different from that one needed in MATLAB/SIMULINK, where the integrators are black boxes.

Many thanks in advance for any help.

Best regards,
Daniele


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on May 30, 2008, 08:37:57 pm
1. Almost all the simulation were integrated with RK4.
2. Most of the second order ODE should be able to break into two first order equation.
3. I would suggest you try Easy Java Simulations (EJS) (http://www.phy.ntnu.edu.tw/ntnujava/index.php?board=11.0).
The code you got was created almost 10 years ago with JDK1.0.2.  I switch to EJS since 2001 and it will be much easier for non-programmer to create simulation.


Title: Re: Kepler Motion
Post by: Daniele on May 30, 2008, 08:56:04 pm
Hi!
Thank you very much for your prompt replay. At the moment I am using eclipse as IDE, do you think it is a good way to start?

I think that most of the problem is to understand the way an OO application works: do you think it would be possible to you to prepare a simple simulation for a 3D circular orbit around the earth? That would be a nice way to start, in order to implement new features like elliptic orbits, perturbations due to the earth oblateness, drag, third body and, most of all, understand the technique involved in this example.

Best regards,
Daniele Romagnoli


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on May 30, 2008, 11:40:52 pm
Eclipse is a good IDE for general purpose programming. But EJS is designed for science teacher or students. Please check out
Easy Java Simulations: a software tool to create scientific simulations in Java (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TJ5-4B3NPMC-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3fa46ca6bd6f771182b485540646ff2f) which is written by EJS original author: Francisco Esquembre
and do not forget to visit Offcial EJS WiKi Page (http://fem.um.es/EjsWiki/)

I think you will like it!


Title: Re: Kepler Motion
Post by: pdnoerd on August 15, 2008, 10:34:52 am
Nice demonstration

Some spelling errors:

(Java Simulaions in Physics)
should be
(Java Simulations in Physics)  (you left out a "t")

"16 centry" should be "16th century"

"Danish bobleman Tycho Brahe" should be "Danish nobleman Tycho Brahe"

Also, someplace I saw "summerized" which means "made ready for summertime" but you want "summarized".  To "summerize" is to fix the air conditioner, for example.

Sorry - I know you start with a different language - just trying to help
Peter


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on August 15, 2008, 04:58:16 pm
Thank you! I have corrected the message according to your suggestion.


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on January 09, 2009, 10:20:58 pm
Try to compare the above motion with the following model.



Title: Re: Kepler Motion
Post by: sharonk868 on January 14, 2010, 06:46:05 pm
Could you at least explain what you want to create? What kind of simulation? What you want to show in the simulation?
Do you have the formula now? What are the form of your formula? What is your model for the simulation?
There are so many information which you did not provide.
I can not read your mind.

I think you also need to learn: How to ask a question effectively?  How to explain your problem?
If I do not have a very clear picture of what you really want to do. There is no way I can help.


I also think so.
Thanks you for the post.
Hi guys, Im a newbie. Nice to join this forum.
-*-


Title: Re: Kepler Motion
Post by: TraceyTrias on January 22, 2010, 10:44:36 am
Thanks a lot. It is very helpful to me... I really needed that.. Thank you so much.

-*-


Title: Re: topic9
Post by: cjamesha on March 06, 2010, 03:22:46 pm
You should have received source code in your email box now.
I want to start writing simulation for electronic circuits. Could you send me source code for keplers laws?

C. James


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on March 06, 2010, 10:28:29 pm
You can download it by yourself (attachement file under the first message).
However, the code was written more than 10 years ago with JDK1.0.2.

I would suggest you to lean EJS. It will be much easier to create simulation with EJS.
There are several circuit related simulation created with EJS, Please check out Electromagnetism (http://www.phy.ntnu.edu.tw/ntnujava/index.php?board=16.0) board under  Easy Java Simulations (2001- )  (http://www.phy.ntnu.edu.tw/ntnujava/index.php#3) category.


Title: code of the kepler's motion applet
Post by: physics4ever on May 07, 2010, 02:57:18 am
hello
would you send me the code of the kepler's motion applet ,
i am in need for it
thanks for your help  :)


Title: Re: Kepler Motion
Post by: Fu-Kwun Hwang on May 07, 2010, 08:38:40 am
The source code is available as attached file under 1st message (where you saw the simulation).
May be you did not look at the whole message so that you did not find it.
Please download it by yourself. ;)


Title: Re: Kepler Motion
Post by: physics4ever on May 07, 2010, 10:28:42 pm
Thank you for you note and I have downloaded it .
I appreciate your help.
sorry for bothering you. I haven't noticed the attachement from the very beginning
 :)


Title: Re: Kepler Motion
Post by: jenny.smith on July 23, 2010, 08:02:34 pm
Well i have lost doubt regarding the Kepler Motion,but after going through post its sorted out great work.


Title: Re: Kepler Motion
Post by: sammys4travel on November 15, 2013, 08:48:37 am
hi,
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Title: Re: Kepler Motion
Post by: diinxcom on December 14, 2014, 05:52:13 pm
-*-
Just Bookmark..
I am new here.. I hope can get many thinks from this forum...


Title: Re: Kepler Motion
Post by: seyf-educ on October 06, 2016, 06:00:18 am
thank you for this post  ;)