The need of Newtons first law of dynamics

by geniusno.198
Tags: dynamics, newtons
lugita15 is offline
Feb19-12, 11:32 PM
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Quote Quote by DaleSpam View Post
There were other theories (Aristotle) that claimed that motion in a straight line at a constant speed required a constant force.
A fascinating bit of trivia is that Aristotelian physics did not refer to the thing that moved an object forward as a "force" - that's a word that came to have it's modern meaning during the Newtonian paradigm. The word that was historically used was "momentum": they thought an object at rest stayed at rest, and the only reason an object would ever move was because it was acted on by an external momentum. This was divided into two categories: natural momentum due to the four elements, like objects made of Earth having a downward momentum which makes them false, and violent momentum due to the random swerving of objects which is what allows humans to move around.
Ken G
Ken G is offline
Feb19-12, 11:38 PM
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It sounds like that for Aristotle, the word "momentum" meant something close to "intention to move", whether conscious intention or the intentions of the natural order. That was the big disappointment-- Newton showed that a much more useful way to think about motion was that only the changes are "intentioned". That left a level of unintentioned (inertial) behavior that the ancients would have found quite distressing indeed, and probably could not have accepted without a radical change in world view that we take more or less for granted today.

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