The physics of our simulator are based largely on those embedded in
the simulator used by the the Dynamo group [SahotaSahota1993] with some
minor adjustments. The ball has a radius of 5.0 units, mass of 0.333
units, and a drag of 30 units/sec 
. This value of drag is typical
for a ping-pong ball (30 cm/sec 
).
The agents are all 40.0 units long by 20.0 units wide with a mass of 10.0 units. The agent's position is updated according to the steering and throttle commands it receives using the fourth-order Runge-Kutta formula [PressPress1988].
Collisions between objects in the world are handled as follows. The ball bounces off walls elastically and stops if it enters a goal, while agents stop if they collide with one another or with a wall. Collisions between the ball and an agent take into account momenta of the colliding objects as well as the corners on the agents.