Can't we say vector or scalar quantity is relative thing

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Discussion Overview

The discussion revolves around the nature of vector and scalar quantities, specifically questioning whether these classifications are relative. Participants explore examples such as area and pressure, debating their scalar or vector status and the implications of these classifications.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant suggests that area can be considered a scalar quantity when expressed in specific units, but also argues that in certain contexts, such as the orientation of a surface, it may be treated as a vector.
  • Another participant asserts that area is fundamentally a scalar, but acknowledges that the specific shape of a surface could introduce vector characteristics, raising the idea of relativity in classification.
  • A different viewpoint introduces tensors, arguing that the discussion of scalars and vectors is limited and that quantities like speed and pressure can be treated as scalars when direction is not a concern. This participant contends that the classification is not relative but rather arbitrary based on convention.

Areas of Agreement / Disagreement

Participants express differing views on whether area and pressure should be classified as scalar or vector quantities, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

Participants reference specific cases and conventions in the classification of physical quantities, highlighting the dependence on context and definitions without reaching a consensus.

samieee
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Can't we say vector or scalar quantity is relative thing!

We all know that physical quantities are expressed as vector or scalar quantities.Now let consider 'area',if I say my house is 2000 sq.feet in that sense area may be called scalar but area of a surface is a vector quantity[either upward or downward direction].Now another example is pressure.It is much debatable whether pressure is scalar or vector.So we can solve the dilemma by saying that the whole thing is relative,don't we?
 
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The 'area' is a scalar. The specific shape of some square is a vector. Saying "2000 square feet" loses information as to whether it is long or skinny, or golden ratio, or square; as well as which direction is normal to that floor plan.
 


yes area is scalar but some specific cases it is vector[area of surface or plane] so can't we call it relative thing?
 


Ever heard of tensors? The world is not completely described by scalars and vectors alone.

Your point is somewhat moot, because the same applies with speed and velocity. When we don't care about direction, it suffices to simply use speed, as in 1/2 m v^2. Similarly, when we don't care about the orientation of a given surface, we can simply use its area, without a specified normal vector. The exact same thing applies for pressure. It's not relative, and in a sense you could argue that these quantities are fully described by a vector and we merely chop off the unnecessary information (make them scalars) when it is convenient for us. But it's certainly not relative. What it is is arbitrary, since for a given surface the choice of normals is completely by convention. It's really not a dilemma at all.
 

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