Oscillatiors are all around us. Examples of periodic motion are children on a swingset or the pendulum in your clock swinging back and forth. Something is periodic if it can be shown to repeat with a specified time interval.
Sometimes these oscillators meet special conditions and exhibit simple harmonic motion. This happens if the displacement from equilibrium position is proportional to the restoring force on the object. An example of simple harmonic motion (SHM for short) is a box hanging from a spring. When an object exhibits SHM, it is also governed by several equations that make finding the accelerations, velocities, and positions much easier. Try some examples below and see what we mean.