Foundational Assumptions in Physical Theory

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Section B.1 Foundational Assumptions in Physical Theory

Subsection B.1.1 Approximate Assumptions valid in the Classical Limit

Assumption B.1.1. Newton’s Laws.

Law of Intertia:
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$\displaystyle F=ma$
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Action-reaction
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🖇️ Linked Notes:

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🔖 References:

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Subsection B.1.2 Thermodynamics & Statistical Mechanics

Assumption B.1.2. The Laws of Thermodynamics.

First Law of Thermodynamics: Energy is always conserved. Therefore, it can neither be created nor destroyed. However, it can be transformed from one form to another.
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The Second Law of Thermodynamics (Clausius statement): Heat cannot spontaneously flow from a colder object to a warmer object without some external work being done.
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- Importantly, this law establishes directionality of heat transfer.
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Third Law of Thermodynamics: Defines entropy as Boltzmann entropy (see Definition 1.2.2). Consequently, this definition implies that absolute zero temperature cannot be reached in a finite number of steps (i.e., it is physically impossible).
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🖇️ Linked Notes: Entropy in Statistical Mechanics 1.2.2

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🔖 References: [Introduction to Heat Transfer]

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