Khan Academy on a Stick
Oscillatory motion
Pendulums. Slinkies. You when you have to use the bathroom but it is occupied. These all go back and forth over and over and over again. This tutorial explores this type of motion.

Introduction to harmonic motion
Intuition behind the motion of a mass on a spring (some calculus near the end).

Harmonic motion part 2 (calculus)
We test whether Acos(wt) can describe the motion of the mass on a spring by substituting into the differential equation F=kx

Harmonic motion part 3 (no calculus)
Figuring out the period, frequency, and amplitude of the harmonic motion of a mass attached to a spring.
Harmonic motion
Every watch a slinky gyrate back and forth. This is harmonic motion (a special class of oscillatory motion). In this tutorial we'll see how we can model and deal with this type of phenomena.