Digital bits on a 12.0-cm diameter audio cd are encoded along an outward spiraling path that starts at radius r1=2.5cm and finishes at radius r2=5.8cm. the distance between the centers of neighboring spiral-windings is 1.6μm(=1.6×10−6m). part a determine the total length of the spiraling path. [hint: imagine "unwinding" the spiral into a straight path of width 1.6μm, and note that the original spiral and the straight path both occupy the same area.]