Does the inertia of an object ever change?

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Discussion Overview

The discussion revolves around the concept of inertia and whether it changes based on the object's location or conditions, such as being on the surface of the Earth, in orbit, or in outer space. It touches on both linear inertia and moment of inertia, exploring theoretical implications and definitions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if inertia changes based on location, specifically comparing scenarios on Earth, in orbit, and in outer space.
  • Another participant suggests that inertia is an innate property of the body, implying it does not change regardless of external conditions, referencing the equation F(net)=ma.
  • Some participants differentiate between linear inertia and moment of inertia, noting that the latter depends on mass distribution and the amount of mass.
  • One participant emphasizes that inertia is an abstract concept and suggests using the term "inertial mass" for clarity, stating that inertial mass is equivalent to mass and questioning the complexity of the original question.
  • There is mention of the relationship between inertial mass and gravitational mass, referencing general relativity's position on their equivalence.

Areas of Agreement / Disagreement

Participants express differing views on whether inertia changes based on conditions, with some asserting it remains constant and others exploring the nuances of linear versus rotational inertia. The discussion does not reach a consensus.

Contextual Notes

Participants highlight the need for clarity in definitions, particularly between inertia and inertial mass, and the implications of mass distribution in rotational scenarios. There are unresolved aspects regarding the nature of inertia in different contexts.

Balsam
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If the mass of an object is the same, does the inertia ever change. For example, is the inertia of a person different if they are on the surface of the Earth than if they are orbiting Earth or in outer space?
 
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This question would probably be best served by a discussion of inertia in the General Physics forum. I'll move it there.
 
Perhaps have a look at the difference between inertia (in a straight line) and the moment of inertia (rotation).
 
I'm not too sure about this, but I don't think it does.. Regardless of where the body is or what type of force is acting on it, its motion is dictated by F(net)=ma
So it looks like inertia is an innate property of the body
 
No, Inertia does not change, it is mass related and it is the resistance to change of motion
 
That's true for linear inertia. For rotation the moment of inertia depends on the distribution of the mass as well as the amount of mass.

T = Iα

where T is Torque, I is the moment of Inertia and α is the angular acceleration
 
Inertia is a term used for an abstract concept or law, not an extrinsic quantity for a system. If you want a quantity, it's better to say inertial mass, which is probably what you mean by your context. Of course, inertial mass is just the same thing as mass, so your original question is trivial. It is possible that there are two kinds of mass, inertial mass and gravitational mass, but general relativity tells us that these are the same thing.
 

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