Physics

Classical Mechanics

This guide helps you get your bearings in Classical Mechanics before you start exploring the interactive timeline, framework graph, and concept maps.

Before You Dive In

Start with Newtonian Mechanics if you're new to physics — it's the foundation everything else builds on.
The big story is successive reformulations: Newton → Lagrange → Hamilton, each more general but describing the same physics.
Quantum Mechanics didn't "replace" classical mechanics — it's still the correct description at everyday scales.
The Lagrangian and Hamiltonian formulations look abstract at first but they unlock all of modern physics.

LagrangianA function (kinetic minus potential energy) that encodes a system's dynamics.

Phase spaceThe space of all possible positions and momenta of a system.

HamiltonianEnergy function on phase space; generates time evolution.

Degrees of freedomThe number of independent coordinates needed to describe a system.

Conservation lawA quantity that doesn't change over time, usually linked to a symmetry via Noether's theorem.

"Lagrangian mechanics is different physics from Newtonian mechanics" — it's the same physics in a different mathematical language.

Confusing "classical" with "outdated" — classical mechanics is used daily in engineering, astrophysics, and robotics.

Thinking Newton's laws are axioms — they're derivable from the principle of least action.

Open the interactive view and scan the framework timeline. Which frameworks came first? Which ones overlap? Where are the big transitions?

Click into individual frameworks to read what each one claims, where it came from, and how it relates to its neighbors.

See how the key ideas within a framework connect. This is useful for figuring out what to learn first and what depends on what.

Take the quiz for any framework you've read about. It's a quick way to find out whether you actually understood the core ideas or just skimmed them.