All the laws of classical mechanics are implied by Lagrange's Equations. [Look it up.]
Noether's famous theorem states that:
1. If a system is a system is translation invariant, then all three components of linear momentum are conserved;
2. If a system is time invariant, then energy is conserved;
3. If a system is rotation invariant, then all three components of angular momentum are conserved.
#2 above implies that energy is conserved and cannot be extracted from any system, so long as the system is time invariant.


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- Ken C August 29, 2025, 1:32 am
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