The SketchPhysics Railgun/Coilgun

I have been trying to post this since yesterday but server response has been so slow that it times out every time until now.
This model uses the positive/negative property of the magnetic property in SP 3.2 to greatly accelerate a projectile to a target. All the "coils" are active and the precise values for all the global and individual variables are critical as is the exact placement of the projectile. The model is extremely sensitive to initial conditions.
The sensitivity to initial conditions is because this model takes advantage of a quirk in the programming to achieve the acceleration. When the magnetic object passes through a pair of coils if the timing is precisely right it will get a boost because of the granularity of the velocity calculations. If the attracting force gives the object velocity v at distance d before the crossover point the object will then be placed by the math in the repulsive zone on the next frame. Because of the exponential algorithm used to determine the fall off of the forces if that new position happens to be very close to the repelling coil the succeeding calculation will give the object a new much higher velocity. When the next frame is calculated the distance traveled will be so large that the new higher velocity will place the object far away from the attracting coil so that the forces do not balance. This granularity is a weakness of all numerical methods that are used to calculate motion.
http://sketchup.google.com/3dwarehouse/details?mid=239f00456d279ceae845c056d1647575

I have upgraded the model significantly including a sound effect, just for fun.
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