Average Speed in Kinetic-Molecular model

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Discussion Overview

The discussion revolves around the assumptions made in the Kinetic-Molecular model regarding the velocity components of gas molecules, specifically the idea that the squares of the x, y, and z velocity components are considered equal. The scope includes theoretical aspects of statistical physics and the foundational principles of the model.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the validity of assuming that the squares of the velocity components are equal in the Kinetic-Molecular model.
  • Another participant suggests that the assumption is based on the average value of the squares of the velocity components and is a basic teaching point, while also noting that it is proven in advanced statistical physics through the theorem of equipartition.
  • A third participant references the theorem of equipartition and provides a link to a Wikipedia article for further reading.
  • A later reply indicates that the initial question has been addressed satisfactorily by the responses received.

Areas of Agreement / Disagreement

Participants express differing levels of understanding regarding the assumption of equal velocity components, with some clarifying the basis of the assumption while others remain uncertain about its implications. The discussion does not reach a consensus on the necessity or validity of the assumption.

Contextual Notes

The discussion does not resolve the underlying assumptions about the velocity components or the conditions under which the theorem of equipartition applies.

Ibraheem
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Hello,

In the Kinetic-Molecular model for gas molecules in a container it is assumed that the square of the x-y-z velocity components is the same, how is it possible that we assume this?
 
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Why would you feel that one component should be more, or less, than another?
By the way, the assumption is made of the average value of the squares of the components of the velocity.
Also, it is an assumption when the topic is taught at a basic level. In advanced course in statistical physics, it is proved. It is called the theorem of equipartition.
 
Thanks for the replies, I can see why this is the case now.
 

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