(Maybe that page should redirect here: http://robocode.sourceforge.net/help/robocode.faq.txt)
It contains a lot of useful information about the exact physics of robocode.
Additional useful info can be found here:
http://robocode.alphaworks.ibm.com/help/physics/physics.html
http://robocode.alphaworks.ibm.com/help/scoring/scoring.html -- Ph