A compact disc $($CD$)$ stores music in a coded pattern of tiny pits ${10}^{-7}m$ deep. The pits are arranged in a track that spirals outward toward the rim of the disc; the inner and outer radii of this spiral are $25\mathrm{.}0$ mm and $58\mathrm{.}0$ mm $,$ respectively. As the disc spins inside a CD player, the track is scanned at a constant linear speed of $1\mathrm{.}25\frac{m}{s}.$