Simple Harmonic Motion in Physics

Simple harmonic motion is what happens whenever the force pulling a body home grows in proportion to how far it has strayed. Springs do it, pendulums do it for small swings, and so does the vibration of a bridge or a molecule. The signature is that the acceleration always points back towards the centre and is proportional to the displacement, which makes the motion repeat with a period that never depends on how far the body swings. The blocks give that force and the timing it produces, the displacement, speed and acceleration at any instant, the energy that sloshes between kinetic and potential twice each cycle, and what happens once damping and driving are added.