NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/
April 18, 2021, 02:56:59 am

First time is the lat time. ...Wisdom

 Pages: [1]   Go Down
 Author Topic: Satellite motion  (Read 18475 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
Fu-Kwun Hwang
Hero Member

Offline

Posts: 3086

 « Embed this message on: August 28, 2007, 03:34:20 pm »

You will find two simulations for satellite motion due to the gravitation force between satellite and massive object(center one with cyan color).
Which one is the correct simulation? The one will rotate or another one which does not rotate?

You can pause the simulation. Change the location or velocity of the satellite when velocity vector is visiable, then press 'play' button again. Enjoy it!
-*-

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!
 Logged
lookang
Hero Member

Offline

Posts: 1796

http://weelookang.blogspot.com

 « Embed this message Reply #1 on: September 05, 2007, 12:23:15 am »

Hi prof hwang,

Q1: can you demonstrate how to wrap a world map onto the circle(sphere) in 3D view ?
http://science.nasa.gov/Realtime/JTrack/3d/JTrack3D.html

there is a non rotating Earth

many people can't visualize the meaning of geostationary orbit, i hope to help make an applet.

Q2: why is the xml file you declare GM = R*R instead of using the G = 6.67*10^-11 and M = 6.0x10^24 ?

the rest still thinking, those i know i post here for others to learn

Model constraint page:
cta=-Math.atan2(x,y); // cta is angle of satellite from origin which is earth comment lines by weelk
r=Math.sqrt(x*x+y*y); // r is radius of rotation comment lines by weelk
if(r>xmax*scale)scale=r*1.2/xmax; // just a way the scale the simulation 1.2 times bigger if the radius in getting bigger than xmax*scale instead of autoscale all the time comment lines by weelk

Model custom page:
double r,r2,r3,cst;
public double getA (double x, double y) {
r2=x*x+y*y;
r3=r2*Math.sqrt(r2);
return -GM*x/r3; //clever way of function getA (x,y) acceleration along each axis comment lines by weelk
}

I was hoping i can modify your codes to make a realistic earth with satellite in 3D view.

i will later add potential versus distance, mass of satellite changeable.

and others can use your template to make applets to suit their needs.

thanks
 « Last Edit: September 05, 2007, 12:36:36 am by lookang » Logged
Fu-Kwun Hwang
Hero Member

Offline

Posts: 3086

 « Embed this message Reply #2 on: September 06, 2007, 10:08:36 pm »

The applet created by NASA was running with real time data. That is a good resource.
I believe their world map was draw with available data. It is not a combination of a static graphs in a 3D environment.
If you can find data for the earth surface. You can draw it with polygon element easily.

 Logged
lookang
Hero Member

Offline

Posts: 1796

http://weelookang.blogspot.com

 « Embed this message Reply #3 on: September 06, 2007, 10:23:50 pm »

i like easy!!!

data refers to graphics ?
 Logged
Fu-Kwun Hwang
Hero Member

Offline

Posts: 3086

 « Embed this message Reply #4 on: September 06, 2007, 10:38:35 pm »

No. Because it is a 3D view of the earth surface. So it was not generate by combination of static graph.
I believe they have all the data for the earth surface. And draw those data points when you change the view angle. I believe the data exists somewhere on the net. But I did not know where it is. And I do have time to search for that now.
 Logged
 Pages: [1]   Go Up
First time is the lat time. ...Wisdom