does a cd rotate at constant angular speed
After debating which to use, they combined the two, which is why DVDs did not make it to America until 1997. Although similar to a CD (Compact Disc), DVDs are more densely packed with data and spin faster. DVDs hold seven times more information and spin three times faster than a CD. The rotational speed, or angular velocity, of a DVD goes between 570-1600 rpm (rotations per minute). The closer to the center of the disc, the faster it spins and which is why there is a range for the angular velocity and not one specific number. This means the read head passes the same length at all times and radii.