What does quantities and dimensions mean?

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Discussion Overview

The discussion revolves around the concepts of quantities and dimensions, specifically whether two quantities can share the same dimensions while being expressed in different units. The scope includes conceptual clarification and exploratory reasoning regarding physical measurements.

Discussion Character

  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants define a physical quantity as something measurable, like velocity or force, and distinguish it from the term 'dimension'.
  • One participant states that "Length" is an example of a dimension, while the "meter" is an example of a unit used to express lengths.
  • Another participant suggests that it is possible for two quantities to have the same dimensions but different units, affirming this with examples of height measured in inches and centimeters.
  • A later reply reinforces the idea by discussing the linear dimensions of a shipping box, which can be measured in various unit systems.

Areas of Agreement / Disagreement

Participants generally agree that two quantities can have the same dimensions while being expressed in different units, though the discussion includes varying explanations and examples without a formal consensus on definitions.

Contextual Notes

Some definitions and distinctions between quantities and dimensions remain implicit, and there may be varying interpretations of the terms used.

elton_fan
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i would like to ask a question about what does quantities and dimension mean in this sentence
is it possible for two quantities to have the same dimensions but different units?

thanks a lot in advance
 
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elton_fan said:
i would like to ask a question about what does quantities and dimension mean in this sentence
is it possible for two quantities to have the same dimensions but different units?

thanks a lot in advance


A physical quantity is something that can be measured, for example, velocity, force, etc. The quantity is expressed in units, which are not to be confused with the term 'dimension'. The term 'dimension' needn't be used, actually.
 
"Length" is an example of a dimension. The "meter" is an example of a unit, one that can be used to express lengths.

- Warren
 
so for example what would be the answer of this question?
i think it's yes
it's true
 
Last edited:
elton_fan said:
so for example what would be the answer of this question?

I'll answer your question with a question. How tall are you in inches? How tall are you in centimeters? Your height dimension is the same, no matter what units you use to express that height.

Think of a particular shipping box. It has linear dimensions of length, width and height. And those dimensions can be measured using various unit systems.
 
thanks a lot i understand now
 

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