Classical Mechanics
Newton's mechanics: how forces, energy, momentum, and gravity govern the motion of everything from a thrown ball to the planets.
A universe of laws
The revolutionary idea that motion obeys exact, universal laws, and that the same rules run a falling apple and a turning planet.
Newton's laws of motion
The three laws (inertia, force equals mass times acceleration, and action and reaction) that underlie all of mechanics.
Energy
Kinetic and potential energy, the work done by forces, and the principle that total energy is conserved.
Momentum
Momentum as mass times velocity, why it is conserved, and how that governs collisions and recoil.
Gravity
Newton's law of universal gravitation, and the insight that the force pulling an apple down also holds the Moon in orbit.
Orbits
How gravity and forward motion combine into orbits, and how Kepler's laws describe the paths of the planets.