Have you ever opened a CD player while the CD was still spinning? I know I have, and with physics I can now explain in more detail the properties of the spinning CD. First, as you open the player, the CD begins to slow down, or accelerate in the negative direction, but continues to spin until it is stopped by the friction between it and the bottom of the CD player.
If you look at the words or pictures on the face of the CD, and track, lets say one letter as it spins, you can determine its tangential acceleration. Tangential acceleration is the radius of the circle on which the letter is spinning times the angular acceleration (the change in angular velocity over a certain time). Because the CD is slowing down the Tangential Acceleration vector is in the opposite direction as the Tangential Velocity vector and is tangent to the circle of motion.
Also, if there are words closer to the center of the CD than the word you are following, they are spinning with the same angular velocity (delta theta/time) as the letters father away, but because they have different radii, their tangential velocity (vt=(r)omega) and therefore tangential acceleration (at=r(alpha)) are different.
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