Why do we say Objects at rest tend to stay at rest?

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Discussion Overview

The discussion revolves around the interpretation of Newton's first law of motion, particularly the statement that "a body at rest tends to stay at rest." Participants explore the implications of motion and rest in the context of relativity and the nature of reference frames, questioning the validity of the concept of "true rest" in a universe where all objects are in motion relative to one another.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that all observable objects are in motion, suggesting that the statement about bodies at rest is misleading and should be framed in terms of relative motion.
  • One participant questions whether it is possible to define a body as being at "true rest," proposing that if such a state existed, it might behave differently, such as starting to spin without an initial velocity.
  • Another participant emphasizes that the concept of inertia should be reconsidered in light of the understanding that there is no absolute frame of reference, as supported by the principles of relativity.
  • Some participants assert that motion is always relative to a chosen reference frame, and that it is possible to define a body as at rest within a specific coordinate system.
  • There is a challenge to the idea that we cannot create something at rest, with a participant stating that it is feasible to define a body as at rest by constructing an appropriate coordinate system.

Areas of Agreement / Disagreement

Participants express differing views on the concept of rest and motion, with no consensus reached on the validity of "true rest" or the implications of relativity on Newton's first law. The discussion remains unresolved regarding the interpretation of these concepts.

Contextual Notes

The discussion highlights the limitations of defining rest and motion without considering the chosen reference frame, as well as the complexities introduced by relativistic physics. The assumptions underlying the statements made by participants are not fully explored.

AlberWiesbauer
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Science wants to be correct,
Every observable object on the planet is not at rest, we are all moving in space.
Have any calculations been attempted to add a constant or variable to make calculations not
start at rest, but at a certain motion?
How can scientists reasonable say a statement that "a body at rest tends to stay at rest?"
We can only say a body relatively at rest, but this is an illusion since all objects observable to us move in space at a rate which apparently is increasing, due to the current observation of the expansion of the universe.

We would could only test what we observe, "a body in motion tends to stay in that motion until altered." We cannot assume "a body at rest tends to stay at rest." Because we cannot create at this time something on this planet at rest in the universe.

-Albert Wiesbauer
 
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By having deteremined we are not at rest, we should rethink the idea of inertia. Maybe if something is set into space at true rest it would start to spin without having a velocity to keep it from spinning. Once velocity is added things could act different. Is there a way to disprove this?
 
What you say about "true rest" seems to suggest that the universe has some absolute frame of reference against which to measure such a thing. Special and general relativity (and I suppose even Galilean relativity) say that such an absolute reference frame doesn't exist, only relative velocities have meaning.

These ideas have served us well and there is nothing to suggest that an absolute frame of reference for the universe exists.
 
AlberWiesbauer said:
By having deteremined we are not at rest, we should rethink the idea of inertia. Maybe if something is set into space at true rest it would start to spin without having a velocity to keep it from spinning. Once velocity is added things could act different. Is there a way to disprove this?

Motion is always relative to some referential. There is no true rest. The rest in Newton's 1st law is taken as relative to some inertial referential.
 
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AlberWiesbauer said:
Every observable object on the planet is not at rest, we are all moving in space.
This is not exactly correct either. Whether you are moving or at rest depends on the coordinate system that you choose. You can certainly choose one where you are at rest, and you can also choose one where we are all moving in space. Both are correct and the math works out correctly in either case, but there is no sense in which one inertial coordinate system is preferred over another.

AlberWiesbauer said:
We cannot assume "a body at rest tends to stay at rest." Because we cannot create at this time something on this planet at rest in the universe.
Yes, we can. Not only can we do this, it is easy to do. All we have to do is to define a given body to be at rest at some moment and build our coordinate system accordingly.
 
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