Unit 01 · Physics 1
Classical Mechanics
The first semester of university physics, from a cart on a track to a planet around a star.
Work through them in order: each lesson assumes the one before it. Every lesson asks you to commit to a prediction, then lets you test it against a simulation of the real equations.
- 01
Motion in One Dimension
Position, velocity and acceleration, and why a graph's slope tells you something its height never will.
Topics: Position and displacement · Velocity as a slope · Acceleration · Constant-acceleration equations
40 min3 checkpoints - 02
Projectile Motion
Two independent motions happening at once, and what air resistance does to that convenient fiction.
Topics: Velocity components · Independent horizontal and vertical motion · Flight time and range · Air resistance
19 min2 checkpoints - 03
Newton's Laws & Free-Body Diagrams
Why a moving object needs no force to keep moving, and how to draw what is actually acting.
Topics: Newton's three laws · Free-body diagrams · Net force and acceleration · Sliding friction · Third-law pairs
50 min9 checkpoints - 04
Friction & Inclines
Static friction rises to match the push, up to a limit, and there is a ramp angle where it finally gives up.
Topics: Normal force on a ramp · Static and kinetic friction · The critical angle
16 min2 checkpoints - 05
Uniform Circular Motion
Constant speed, changing velocity, and the outward force that does not exist.
Topics: Centripetal acceleration · Centripetal force · Motion after release
18 min2 checkpoints - 06
Work & Energy
A bookkeeping system so reliable that you can answer questions without ever solving the motion.
Topics: Work · Kinetic and potential energy · Conservation of energy · Friction losses
18 min2 checkpoints - 07
Momentum & Collisions
What survives a collision, what doesn't, and why the centre of mass never notices.
Topics: Momentum · Conservation in collisions · Coefficient of restitution · Centre of mass
15 min2 checkpoints - 08
Rotation, Torque & Rolling
Why a hoop always loses the race, and why making it heavier will not help.
Topics: Moment of inertia · Torque · Rolling without slipping
15 min2 checkpoints - 09
Angular Momentum
Pull your arms in and you speed up. Nothing pushed you, so where did the energy come from?
Topics: Angular momentum · Conservation of angular momentum · Rotational kinetic energy
13 min1 checkpoint - 10
Gravitation & Orbits
One inverse-square law, and every conic section follows from it, including the orbits that escape.
Topics: Newton's law of gravitation · Elliptical orbits · Kepler's laws · Escape
18 min2 checkpoints - 11
Simple Harmonic Motion
The one differential equation that shows up everywhere, and the approximation hiding inside every pendulum clock.
Topics: Restoring force · Period and frequency · Phase · The pendulum
17 min2 checkpoints - 12
Damping, Driving & Resonance
Push at the right rhythm and small forces build large motion. The right rhythm is not quite where you would guess.
Topics: Damping regimes · Driven oscillation · Resonance · Transients
14 min2 checkpoints