Unit 7: Oscillations
A mass on a spring, a pendulum, a guitar string: things that move back and forth in a repeating way. Simple harmonic motion is the cleanest case, and it pulls together forces, graphs and energy from the earlier units.
What you will master
- Recognise simple harmonic motion: a restoring force proportional to the displacement from equilibrium (F = −k x).
- Find period and frequency: T = 1 / f, T = 2π √(m / k) for a mass on a spring and T = 2π √(L / g) for a pendulum at small angles, and say what does not change the period (the amplitude).
- Read and draw position, velocity and acceleration graphs of SHM and use x(t) = A cos(2π f t).
- Track energy in an oscillator: the total energy ½ k A² is shared between kinetic and potential energy during each cycle.
Rule used on every page: measure x from the equilibrium position, and state which way is positive.
Topics
Do them in order. Each one follows the same path: story, idea, play, worked examples, practice, common mistakes. Then play the games and finish with the practice set.
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How this unit connects
Uses spring forces from Unit 2 (2.8), the motion graphs of Unit 1 (1.3) and conservation of energy from Unit 3. The speed is largest at equilibrium; the acceleration is largest at the ends, where the velocity is zero.