22/2 THE EFFECTS OF CONSTANCY 



The events may be viewed in two ways, which are equivalent. 



We may treat the change of k as a change of parameter to the 

 2-variable system x v cc 2 , changing their equations from (2) 

 above to (3) (S. 21/1). The field of the 2-variable system will 

 change from A to B in Figure 22/2/1, where the dotted line at X 



A B 



Figure 22/2/1 : Two fields of the system (x t and x 2 ) of S. 22/2. 

 unbroken elastic the system behaves as A, with broken as B. 

 the strand is stretched to position X it breaks. 



With 

 When 



shows that the field to its right may not be used (for at X the 

 elastic will break). 



Equivalent to this is the view which treats them as a 3- variable 

 system: x v x 2 > an d k. This system is state-determined, and has 

 one field, shown in Figure 22/2/2. 



Figure 22/2/2 



Field of the 3-variable system. 

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