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Part A On a 12.0-cm-diameter audio compact disc (CD) digital bits of information

ID: 1782447 • Letter: P

Question

Part A On a 12.0-cm-diameter audio compact disc (CD) digital bits of information are encoded sequentially along an outward spiraling path. The spiral starts at radius R1 2.5 cm and winds its way out to radius R2 5.5 cm. To read the digital information, a CD player rotates the CD so that the player's readout laser scans along the spiral's sequence of bits at a constant linear speed of 1.23 m/s. Thus the player must accurately adjust the rotational frequency f of the CD as the laser moves outward Determine the values for f (in units of rpm) when the laser is located at R1 Express your answer using two significant figures rpm Submit My Answers Give Up Part B Determine the values for f (in units of rpm) when the laser is located at R2 Express your answer using two significant figures pm Submit My Answers Give Up

Explanation / Answer

a) f = v / 2 pi R1

= (1.23) / (2 pi * 0.025)

= 7.83 rev/s * (60 s / 1 min)

f = 470 rpm

b) f = v / 2 pi R2

= (1.23) / (2 pi * 0.055)

= 3.56 rev/s * (60 s / 1 min)

f = 213 rpm