I keep getting “Simple harmonic motion” questions wrong in Oscillations & Waves. What's the trap?
assuming every back-and-forth motion is SHM.
The usual trap: assuming every back-and-forth motion is SHM. How to avoid it: only a linear restoring force (∝ −x) gives true SHM. Go back to the definition — oscillation where the restoring force is proportional to and opposite the displacement, F = −kx.
Key point
Simple harmonic motion
Common mistake
assuming every back-and-forth motion is SHM.
Memory tip
only a linear restoring force (∝ −x) gives true SHM.
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