Springs, pendulums and waves: anything that repeats.
Simple Harmonic Motion Damped & Driven Oscillations (Resonance) Normal Modes: Coupled Oscillators Time Averages of sin² and sin·cos Damped Free Oscillator: Q, Phase, Decrement, Critical Damping Scale Spring Constant Velocity and Driving Force in Phase Average Stored Energy Car Suspension: Spring Constant & Bounce A Vibrating Floor: Resonance Under Footsteps A Loudspeaker Cone: Speed & Acceleration Spring Calculations Spring Started with a Push Energy Calculations Doubling the Amplitude Measuring g Moment of Inertia Measurement Simple Pendulum with Damping Wave Motion: 1D String → 2D Ripples → 3D Sphere Waves on a String: Speed and Reflection Superposition & Standing Waves Harmonics: Strings & Pipes Dispersion & Group Velocity Sound: Doppler Effect & Intensity Organ Pipe & Flute: Open vs Closed Pipes Tuning by Beats Doppler Echoes: A Bat and a Radar Gun Two Loudspeakers: Where the Quiet Spots Are Wave vs Particle Velocity Pulse on a Wire Echolocation Earthquake Intensity A Travelling Wave Wave Equation Solution Making a Square Wave Piano String Wave Forms Refraction of an Earthquake Wave Distance from a Lightning Strike Autofocusing with Sound Waves Sound Intensity on the Street Loudspeaker Response Trumpet Players Airplane Roar How Tiny the Displacement Is Piano Strings Frequencies and Wavelengths in the Violin The Pitch Drop of a Passing Ambulance Tuning a Guitar String & Placing the Frets