Simple harmonic motion, period and frequency of springs and pendulums, sinusoidal motion graphs, and energy conservation in oscillators.
🎙 Episode 7
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What's in this episode
0:00 – Intro — What oscillation is and why it shows up everywhere
2:00 – Defining SHM (7.1) — Restoring force proportional to displacement; F = −kx
6:00 – Springs and pendulums — Both produce SHM (pendulums only for small angles)
9:00 – Period and frequency (7.2) — T = 2π√(m/k) for springs; T = 2π√(L/g) for pendulums
13:00 – Why amplitude doesn't matter — The biggest surprise of Unit 7
17:00 – Sinusoidal motion (7.3) — Position, velocity, and acceleration as sine waves
21:00 – When is v max? When is a max? — Equilibrium vs amplitude
25:00 – Energy in SHM (7.4) — Total E = ½kA²; KE and PE trade off
29:00 – Damping — What happens with friction; amplitude shrinks over time
32:00 – Wrap-up — The 3 big ideas in one minute
How to use the podcast
First listen: Play at 1× speed with no distractions. The most important section is "why amplitude doesn't matter" (13:00–17:00) — internalize this and you've avoided the biggest Unit 7 trap.
Second listen: Speed up to 1.25× or 1.5× and follow along with the Cheat Sheet open. Make sure both period equations stick.
Right before the exam: Play at 1.5–2× while reviewing flashcards. Unit 7 is mostly two formulas — repetition makes them stick.