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Reverse Engineering


Building a mathematical model is like building other types of models such as visual models (pictures), verbal models (speech, articles, or books), and sculptures.

Let us consider a simple example of reverse engineering by choosing the transmission system of a car, the mechanisms that convert the circular motion produced by the engine into the forward or backward motion of the car. The circular motion of the engine is measured in rpms, or revolutions per minute using a tachometer.

In the United States the motion of a car is measured in mph, or miles per hour using a speedometer.


Look at your Bicycle

You may get an idea of the general principles of transmission system of a car by considering a bicycle. The gears, chain, and tires of a bicycle convert the circular motion of the pedals into the forward motion of the bicycle. There is a cluster of gears attached to the pedals. The gears have different numbers of teeth. The rear wheel also has a cluster of gears and each gear has a different number of teeths.


If the front derailler is on the 52 tooth gear and the rear derailler is on the 14 tooth gear then each revolution of the pedals causes the chain to move by 52 teeth. Therefore, the rear gear revolves by 52 teeth. Since the rear gear has 14 teeth this produces 52/14 revolutions of the rear wheel. If the diameter of the rear wheel is 27" then each revolution of the pedals moves the bicycle 315.06 inches = 26.25 feet = 0.0050 miles.