Raelifin.com » physics http://raelifin.com Deus ex Machina Sun, 04 Jul 2010 01:45:59 +0000 en hourly 1 Gravitation http://raelifin.com/code/gravitation/ http://raelifin.com/code/gravitation/#comments Sat, 05 Dec 2009 22:04:11 +0000 Raelifin http://raelifin.com/?p=161 SolOne weekend, about a month ago, I threw together a quick simulation of the solar system because I was studying gravitation in school. Since I have some time now I went back and polished it to allow user interaction and remove various glitches. It’s still quite crude, but I’m done dealing with it, so I figured that I’d throw it up here. One of the coolest things it does (IMO) is show the paths of the planets from a non-heliocentric viewpoint.

Everything (code and images) is public domain. Credit is nice, but not necessary. Download code (and runnable jar) here. Created using Slick (Build #266) with LWJGL (2.0b1).

Geocentric Perspective
A Geocentric View of the Universe.

Geocentric Perspective 2
Another Geocentric Perspective.

Jupiter Perspective
View from Jupiter.

Oh, and I almost forgot! One of the other neat things I did with the simulation was “experimentally” measure the speeds of the planets (except Neptune). I looked up average orbital distances and the mass of the sun on Wikipedia and then tweaked the initial velocity of each planet until the orbit looked roughly circular. I did this mostly out of laziness, but I was shocked at how close I had gotten to the real values.

Estimated Speed (km/s) Observed Speed (Average) (km/s)
Mercury 48 47.87
Venus 34.5 35.02
Earth 29.5 29.783
Moon 30.5 30.805
= 29.783 (earth) + 1.022 (relative speed of luna)
Mars 24 24.077
Jupiter 13 13.07
Saturn 9.5 9.69
Uranus 6.8 6.81
]]> http://raelifin.com/code/gravitation/feed/ 1 Playing with Physics http://raelifin.com/code/wall-ball-physics/ http://raelifin.com/code/wall-ball-physics/#comments Sun, 18 Oct 2009 22:18:22 +0000 Raelifin http://raelifin.com/?p=147 Graph of a ball hitting a wallThis weekend, as a side project, I did some modeling of physics concepts I’ve been studying in class. Specifically, conservation of momentum of a system, how the motion of particles can be summed into macroscopic bodies, how forces move through solids in waves, and how quantity of matter (mass) has an impact on acceleration. This is just me playing around, but I thought some people might enjoy seeing what I’m up to.

I’m releasing all the code into the public domain here. Everything is HTML5/javascript (view source to get it), and you’ll need a decent browser (not IE!) for it to work. There’s no user interface, so if you want to change variables or play with it yourself you’ll have to edit the source.

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