Kepler Ellipses


Kepler Ellipses

In this little tutorial we want to set up a very small physics simulation with CindyLab. We want to model a planet orbiting a sun. You should learn in this tutorial how to set up and start running a physics simulation.

After starting Cinderella, go to "add sun" mode by clicking the button in the toolbar. Then add a sun at an arbitrary position. After the sun has been added, an animation control will appear. The animation control is always present when physics elements of CindyLab are present. The view will now look approximately like Figure 1.

Figure 1: A sun is born

Now we add the planet that we want to orbit the sun. The planet needs an initial velocity perpendicular to the sun. Otherwise, it will be attracted directly toward the sun and end up in a singularity. For adding the point go to "add velocity" mode by clicking , and perform a press–drag–release operation somewhere near the sun. When the mouse is pressed the mass-point is created. Dragging creates the force, and releasing finalizes the situation. The picture should now look approximately like Figure 2. If not, you can change the position of the points and of the arrowhead in move mode.

Figure 2: A sun and a planet

Now you can start the simulation by pressing the play button. Most probably, the animation will run too fast. You can change the animation speed with the slider in the animation control. The planet should describe an elliptical path (this is the essence of Keplers third law).

We now want to make the ellipse a little more visible. For this we want to create a trace of point B, the planet, while it is moving. Open the inspector and go to the "Special Appeareance" tab by clicking the button . After point B has been selected, the inspector looks like Figure 3:

Figure 3: Inspecting the planet

Check the "Draw Trace" checkbox. This causes Point B to leave a trace as it moves. Now restart the animation. You will see the ellipse as a trace of the planet, as in Figure 4.

Figure 4: The planet's orbit

We recommend that you carry out several experiments with this configuration. Here are a few proposals:

  • Vary the location of the planet.
  • Vary the speed (the magnitude of the velocity).
  • Vary the direction of the velocity.
  • What happens when more than one sun is present?

Contributors to this page: Richter , Kortenkamp , Kohler and Kramer .
Page last modified on Friday 02 of September, 2011 [16:44:24 UTC] by Richter.

The content on this page is licensed under the terms of the License.

free viagra samplehentai girlsmature pussymilfseeker cialis samplescam clip movie nude webcammother incest order viagra online cialis ukanime rapeparis hilton phone numbers viagra alternatives cialis forum cialis free samplehot girls in pantiesmonster of cocks discount cialis cilias free viagra samplesfree chat rooms cilia structurefree cartoon sex comics buy cialis order viagrafree adult videosplump girl gallerypantyhose gallerycum on her face cheapest cialisbisexual moviestampa bukakehuge black cock thumbnails buy cialis onlineporn star cialis drugwomen having sex cheap generic viagra alternative to viagra natural viagra cheap viagraoral sexteen webcam strip videosnude spanish girlserotic sex cams movies viagra side effectscartoon adultdisney sex animenude blonde hairygang bang swinger cialis viagrabisexual free moviesgay twinkswebcam chat live xxxyoung teens order cialislatina girls thongscum loversjapanese girl viagra cheapyoung japanese girlsmr chews asian beavergangbang squadshoshone indiansmature wiveslive webcam chat girlsfree ebony viagra on lineasian ladyboysteen boys viagra pillsself bondage techniques cailisincest familyfree ebony cheap cialisgay amateur cialis genericbusty asian viagra onlinemature breasts viagra for women free viagrabig boobies cialis generic viagragloryhole gaylatinas in thongs female viagraindian tits viagra 6 free samplesamateur upskirt viagra alternativefree xxx video cialis online discountgalleries of teen girls cialis dosage cheap generic cialisparis hilton pornopussy cat dollsbrutal sexgay peopleblack milfsno tits discount viagrablonde hairy pussyshemale animefree hardcore moviesmom strips for sonfat titscelebrity legsdouble anal levitra vs cialis cialis tadalafil cialis cheapgay bdsmcelebrities exposed viagra generic alternatives to viagra viagra canadabestialitypink porn stars viagra jokesclips of teen sexchicks suck horse cock online viagrasex with horsespainful analglory holes floridafree american bukkake cialis online buy viagrabig cock cum free cialisteen gay porn cialis side effects herbal viagra best price viagra purchase cialis cialis soft tabs cialis vs viagrafree fat girl webcamfree porn movie clipsoral penis suckingebony hardcore viagra pricepantyhose crossed legs cialis and levitralesbiennesblonde boobs buy viagra online