What Makes It Simple Harmonic

You'll learnthe one rule a = −ω²x that defines simple harmonic motion.

Plenty of motion repeats; very little of it is simple harmonic. One rule checks IDs — a = −ω²x — and this file watches it work: the acceleration always points home, grows straight with the displacement, and dies to zero at the very center where the speed is greatest.

8 STEPS · 6 QUICK CHECKS · v2

SHM LAB

Before you start

What you're looking at

A block on a spring sliding back and forth along a track, with displacement and acceleration arrows.

The question

Where along the track is the block's acceleration largest?

Watch for

The acceleration arrow — largest at the ends, zero at the center where the block moves fastest.

What the symbols mean

The emerald arrow is displacement x; the amber arrow is acceleration a; they point opposite ways at every instant.

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