Topic lessons
31 short lessons covering AP Physics 1, AP Physics 2, and AP Physics C: Mechanics and E&M. Each one has the big idea, the key equations, a fully worked example, common mistakes, a practice question, and a link to the simulation that goes with it. Lessons marked AP 1 exam level add exam-style reasoning and practice for AP Physics 1, and lessons marked C-level also include a “Going deeper” section with calculus derivations, extra worked examples and exam-style practice at the AP Physics C standard.
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Vectors, Dot & Cross Products
Components, unit vectors, and the dot and cross products that AP Physics C uses for work, torque, flux and magnetic force.
Kinematics & Motion Graphs
Position, velocity and acceleration, and how to read and connect x–t, v–t and a–t graphs.
Projectile Motion
Two independent motions at once: constant velocity sideways and free fall up and down.
Newton's Laws, Free-Body Diagrams & Friction
Draw the forces, choose smart axes, and apply ΣF = ma, including static and kinetic friction.
Circular Motion
Why moving in a circle needs a net force toward the centre, and how big it must be.
Work, Energy & Power
Energy as bookkeeping: kinetic, potential and thermal, and the work that moves energy between them.
Momentum, Impulse & Collisions
Momentum is conserved in every collision. Kinetic energy isn't always. Plus impulse and the centre of mass.
Torque & Rotational Equilibrium
What makes things turn, and the two conditions for an object to stay perfectly still.
Angular Momentum
Why spinning skaters speed up when they pull their arms in.
Rolling Motion & Rotational Energy
Why a hoop loses a race to a solid sphere, and how energy splits between moving and spinning.
Simple Harmonic Motion
Springs and pendulums: periods, energy swaps and the sinusoidal motion.
Fluids: Pressure, Buoyancy & Bernoulli
Pressure with depth, why things float, and why fast-moving fluid has lower pressure.
Resistive Forces & Terminal Velocity
Velocity-dependent forces, differential equations and terminal velocity.
Conservative Forces & Potential Energy Curves
F = −dU/dx, turning points, and stable and unstable equilibrium on a U(x) graph.
Gravitation, Orbits & Kepler's Laws
Newton's law of gravitation, circular and elliptical orbits, and escape speed.
Thermodynamics & the Ideal Gas
PV = nRT, PV diagrams, and the first law: ΔU = Q + W.
Electric Charge & Charging Methods
Conservation of charge, conductors vs insulators, and charging by friction, conduction and induction.
Coulomb's Law & Superposition
The inverse-square electric force, and adding forces from several charges as vectors.
Electric Field & Electric Potential
Field as force per charge, potential as energy per charge, and equipotentials.
Gauss's Law
Flux through closed surfaces, and fields of spheres, shells and conductors using symmetry.
Capacitors & Dielectrics
C = κε₀A/d, stored energy, and what changes when a capacitor is connected or isolated.
DC Circuits, Ohm's Law & Kirchhoff's Rules
Series and parallel resistors, equivalent resistance, and finding every current and voltage.
RC Circuits
Charging and discharging capacitors, exponential curves and the time constant τ = RC.
Magnetic Force on Charges & Currents
F = qv × B, circular motion of charged particles, velocity selectors, and the force on wires.
Magnetic Fields of Currents & Ampère's Law
Fields around wires and inside solenoids, forces between wires, and Ampère's law.
Electromagnetic Induction: Faraday's & Lenz's Laws
Changing flux induces emf, Lenz's law gives the direction, plus motional emf and LR circuits.
Geometric Optics: Refraction, Lenses & Mirrors
Snell's law, ray diagrams and the thin-lens and mirror equations.
Waves, Sound & Standing Waves
v = fλ, transverse vs longitudinal waves, and harmonics on strings and in pipes.
Interference & Diffraction
Path difference, double slits, diffraction gratings and the wave nature of light.
The Photoelectric Effect & Photons
Light as photons: E = hf, work function, threshold frequency and stopping voltage.
Atomic Energy Levels & Spectra
Quantized energy levels, photon emission and absorption, and hydrogen's spectral series.