PhysicsChapter 3: Simple Harmonic Motion
Simple Harmonic Motion
Simple harmonic motion (SHM)
Definition
Simple harmonic motion (SHM) is periodic motion in which the acceleration of an object is directly proportional to its displacement from the equilibrium position and is always directed toward equilibrium.
At Equilibrium
An oscillating body moves repeatedly about an equilibrium or mean position. Not every oscillation is SHM. For motion to be simple harmonic: a ∝ −x Therefore: a = −ω²x where: `a` = acceleration `x` = displacement from equilibrium `ω` = angular frequency The negative sign shows that acceleration is always opposite to displacement. `x = 0` Therefore: `a = 0` Speed is maximum.
At Extreme Position
`x = ±A` Acceleration magnitude is maximum. Speed is zero.
Restoring Force
Using `F = ma`: **F = −mω²x** Thus restoring force is also proportional to displacement and directed toward equilibrium.
Formula / Key Relation
**a = −ω²x F = −mω²x x = A cos(ωt+φ) ω = 2πf = 2π/T**
Exam preparation
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Review the key facts, formulas and checks before you move on.Simple Harmonic Motion
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SHM
- `a ∝ −x`
- Equilibrium:
- `v = max`
- `a = 0`
- Extreme:
- `v = 0`
- `|a| = max`
60-second revision
- SHM is an oscillation controlled by a restoring acceleration directed toward equilibrium.
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