Compact Disc. A compact disc (CD) stores music in a coded pattern of tiny pits 10^-7m 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 25.0 mm and 58.0 mm, respectively. As the disc spins inside a CD player, the track is scanned at a constant linear speed of 1.25 m/s.
a) What is the angular speed of the CD when scanning the innermost part of the track?
b) What is the angular speed of the CD when scanning the outermost part of the track?
c) The maximum playing time of a CD is 74.0 min. What would be the length of the track on such a maximum-duration CD if it were stretched out in a straight line?
d) What is the average angular acceleration of a maximum-duration CD during its 74.0-min playing time? Take the direction of rotation of the disc to be positive.
2007-02-26 18:55:02 · 1 answers · asked by Paul Wall 2 in Science & Mathematics ➔ Physics
a) omega = velocity / radius
omega = 1.25 / 25 x 10^-3 = 50
b) same technicque as a)
omega = 1.25 / 58 x 10^-3 = 21.55
c) 74mins x 60 = 4440 seconds (length of the CD)
Disk spins at 1.25 ms,
4440 x 1.25 = 5550 metres length
d) Not sure what you are asking here...., but angular acceleration is-: Angular Acceleration = velocity^2 / radius
2007-02-26 22:05:50 · answer #1 · answered by Doctor Q 6 · 0⤊ 0⤋