Demonstrations of Physics Inconsistency with Distance from Origin

This page shows how physics is affected by positional error in both space and time. The demonstations were written in Python with ODE extensions.

Installation

To run the programs on Windows, please follow these instructions:

1. install python 2.4
python-2.4.3.msi
http://www.python.org/ftp/python/2.4.3/

2. edit autoexec.bat (Windows95) or change the environment settings (Windows XP) to add:
SET PATH=%PATH%;C:\python
SET PYTHON=C:\PYTHON\

3. install pyOpenGL
PyOpenGL-2.0.2.01.py2.4 -numpy23.exe
http://pyopengl.sourceforge.net

4. Copy glut32.dll to the C:\python\Lib\site-packages\OpenGL
directory. (This is a *crucial* step.)
glut32.dll
http://www.xmission.com/%7Enate/glut.html

5. install OpenGLContext
OpenGLContext-2.0.0c1.win32-py2.4.exe
http://pyopengl.sourceforge.net/context/
(downloaded from http://pyopengl.sourceforge.net/ )

6. install PIL (python Image Library)
PIL-1.1.5.win32-py2.4.exe
http://www.pythonware.com/products/pil/

7. install pyODE
PyODE-1.1.0.win32-py2.4.exe
http://pyode.sourceforge.net/

Now you can double-click on the tutorial3.py from http://pyode.sourceforge.net/ and it simply runs!

Experiments

The programs linked below perform a number of experiments that are identical except for minor variations: displacements in space or time.
In all cases the experiments drop a box near a stationary box onto a plane. An image of the rest
position of the box was saved. The experiment is repeatable: the box lands in same place each time relative to the stationary one.

Experiment at the origin:
preciseBlocks.py

at origin

Position error

Then the whole experiment wads moved by (10,10,10) and repeated. The box rest position was very different.

displaced by (10,10,10):
preciseBlocks10.py

The image below compares the rest position after running the experiment centered at the origin to when it is run after displacement by (10,10,10).

shift by (10,10,10)

Time Error

The first experiment was repeated with the only difference being
that it was programmed to wait 8000 seconds before dropping the box.
Again the rest position was different.

at time=8000:
preciseBlocksTime8000.py

The image below compares the rest position after running the experiment centered at the origin to when it is run after waiting untile time=8000.

time=8000