> The parallel axis theorem, also known as Huygens–Steiner theorem, or just as Steiner's theorem,[1] named after Christiaan Huygens and Jakob Steiner, can be used to determine the moment of inertia or the second moment of area of a rigid body about any axis, given the body's moment of inertia about a parallel axis through the object's center of gravity and the perpendicular distance between the axes
Horologium Oscillatorium by Huygens: https://en.wikipedia.org/wiki/Horologium_Oscillatorium
Parallel axis theorem: https://en.wikipedia.org/wiki/Parallel_axis_theorem :
> The parallel axis theorem, also known as Huygens–Steiner theorem, or just as Steiner's theorem,[1] named after Christiaan Huygens and Jakob Steiner, can be used to determine the moment of inertia or the second moment of area of a rigid body about any axis, given the body's moment of inertia about a parallel axis through the object's center of gravity and the perpendicular distance between the axes
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Harmonic oscillator: https://en.wikipedia.org/wiki/Harmonic_oscillator
Quantum Harmonic Oscillator: https://en.wikipedia.org/wiki/Quantum_harmonic_oscillator
Pendulum (mechanics) https://en.wikipedia.org/wiki/Pendulum_(mechanics)