NetLogo User Community Models
by David Bowen (Submitted: 05/01/2007)
WHAT IS IT?
This model represents Newtonian Relativity (or Classical Relativity) with a car traveling on top of a traveling railroad flatcar.
HOW IT WORKS
Both the car and the railroad flatcar travel at a set, fixed speed. The speed of the car is set so that it will travel from one end of the flatcar to the other, while the flatcar travels across the speed.
There are three options to set:
Set 1 and 2 before Setup, because they have no effect after Setup. You can flip back and forth between forward and reverse while the model is running.
HOW TO USE IT
Set the switches and sliders as in 1 and 2 above, then click Setup, and then Go.
THINGS TO NOTICE
The distance from the station (left-hand edge of screen) to the rear of the flatcar, plus the distance from the rear of the flatcar to the rear of the car, is equal to the distance from the station to the rear of the car. This is the premise of Newtonian Relativity.
NOTE: Because of rounding errors, the distances will sometimes not add up exatly.
THINGS TO TRY
A first run with show-markers set to Off will illustrate the basic situation, with the car traveling on top of the traveling flatcar. Then set the markers to On to see the distances.
EXTENDING THE MODEL
The model could be extended to show time dilation and space compression at relativistic speeds.
This model uses the new "box" world, where the coordinates do nor wrap around. In the normal torus world, the distance markers flip to the right-hand side as soon as the flatcar reaches the midpoint.
I do not know of other models related to this one.
CREDITS AND REFERENCES
Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.
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