thaler chapter 1

A Word About Vectors

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A Word About Vectors

It is important to recognize that each EKG electrode records only the average current flow at any given moment. Thus, although tiny swirls of current may simultaneously be going off in every direction, each lead records only the instantaneous average of these forces. In this way, out of chaos, some very simple patterns emerge. This concept is really quite simple; an analogy may be helpful. During the course of a soccer match, a goalie may kick the ball many different times to various members of his team (or, if our hypothetical goalie is not very good, the other team). Some balls will go left, others right, and still others straight down the field. However, by the end of the game, the average direction of all of the goalie’s kicks and tosses is likely to be straight ahead, toward the opposing net. This average direction can be represented by a single arrow, or vector .

A

B

( A ) The directions of each of the goalie’s kicks during the course of the game. ( B ) A single vector represents the average direction and distance of all of these kicks.