I don't know much about classical physics(such as lagrangian function), but as i was reading conservation of energy, i came to this theorem and it tells that if a system is symmetrical in certain transformations(such as translation, rotation etc) then it will have a corresponding law of conservation, such as momentum is conserved in translation symmetry and angular momentum is conserved in rotational symmetry, and energy is conserved in time symmetry(adsbygoogle = window.adsbygoogle || []).push({});

I didn't understood the symmetry part, how can we say that time is symmetric and how can we use this theorem to prove conservation of energy?

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# I What does Noether's theorem actually say?

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