Why is acceleration independent of reference frames?

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Discussion Overview

The discussion centers around the concept of acceleration and its independence from inertial reference frames. Participants explore the implications of this independence in both classical and relativistic contexts, questioning how displacement and velocity relate to changes in reference frames.

Discussion Character

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

Main Points Raised

  • One participant questions why acceleration is independent of inertial reference frames, suggesting that if displacement and velocity vary, acceleration should as well.
  • Another participant proposes that the velocity addition formula can be differentiated to derive acceleration, implying a mathematical approach to the question.
  • A participant distinguishes between coordinate acceleration, which varies with reference frames, and proper acceleration, which is invariant and measured by an accelerometer.
  • It is noted that in the classical (non-relativistic) case, while velocity depends on the frame, the change in velocities is frame independent due to the nature of transformations between inertial frames.
  • A later reply acknowledges a misunderstanding about the context of the discussion, indicating that the initial question may have been perceived as more complex than intended.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between acceleration, displacement, and velocity across reference frames. While some clarify distinctions between types of acceleration, no consensus is reached on the implications of these differences.

Contextual Notes

The discussion includes references to both classical and relativistic physics, highlighting the complexity of transformations and the nature of acceleration in different contexts. Some assumptions about the nature of acceleration and reference frames remain unexamined.

Who May Find This Useful

This discussion may be of interest to those studying classical mechanics, relativity, or anyone curious about the foundational concepts of motion and reference frames in physics.

randomgamernerd
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I want to know why is the measurement of acceleration independent of inertial reference frames?
I mean if displacement, velocity varies with change of inertial reference frames, acceleration should vary.
And, one more question: When we say that displacement or velocity varies with change in reference(inertial) reference frames, are we talking about variation in magnitude only or both magnitude and direction. I think it should be both magnitude and direction.
 
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You can derive this directly from the velocity addition formula. Just differentiate it with respect to time.
 
randomgamernerd said:
I want to know why is the measurement of acceleration independent of inertial reference frames?
I mean if displacement, velocity varies with change of inertial reference frames, acceleration should vary.
Hi randomgamernerd, welcome to PF!

In relativity there are two different acceleration concepts and it is important to distinguish between the two of them.

One of them is coordinate acceleration, this seems to be the kind of acceleration you are thinking about. You are correct, length contraction and time dilation make it so that different frames disagree on coordinate acceleration.

The other kind is called proper acceleration. This is the acceleration that you physically feel, the acceleration measured by an accelerometer. This acceleration is invariant, and becomes very important as you transition from SR to GR.
 
randomgamernerd said:
I want to know why is the measurement of acceleration independent of inertial reference frames?
I mean if displacement, velocity varies with change of inertial reference frames, acceleration should vary.
And, one more question: When we say that displacement or velocity varies with change in reference(inertial) reference frames, are we talking about variation in magnitude only or both magnitude and direction. I think it should be both magnitude and direction.
I suppose that you mean the classical (non-relativistic) case.
In this case, even though the velocity depends on the frame, the change in velocities is frame independent.
This is so because in the non-relativistic limit the transformations between inertial frames are just adding some constant ( velocity) which cancel out when you take the difference.

The relativistic case is a little more complex, as already mentioned (Dale's post).
 
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My apologies for my answer. For some reason I thought this was in the relativity section. My response was probably overboard for a basic general physics question.
 
i forgot to give a reply.
Thanks for your answers...
 

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