Bits per meter of a CD

Classical Mechanics Level 2

While a CD player is reading the outer edge of an audio CD the disc spins at approximately 3.33 revolutions per second. The radius of a CD is 0.06 meters and the data transfer rate is 1.2 million bits per second (a bit is the smallest piece of information one can have - it is either a one or a zero). How many bits are stored per meter on the outer rim of a CD to the nearest thousand?

The answer is 956000.

2 solutions

Daniel Liu
Nov 17, 2013

The circumference of the CD is $2\pi\times 0.06=0.12\pi$ . Multiplying this by $3.33$ gives the number of meters passed per second: $0.3996\pi$ m/s. Now we divide 1.2 million bits by this number to get the number of bits per meter: $1200000\div (0.3996\pi)\approx \boxed{956000}$ bits per second.

Nice one (y)

Farhan Atonu I - 7 years, 6 months ago

thanks

Hamza Gillani - 7 years, 6 months ago

bits per meter*

José Renato Zacaroni Barbosa - 7 years, 6 months ago

thanx

jamal ahmed - 7 years, 6 months ago

nice

Abd Elalim Saeed - 7 years, 6 months ago

hmmmm i forgot taking circumference

Juma Khan Zahidi - 7 years, 6 months ago

Sharky Kesa
Nov 22, 2013

Here is the series of equation you must solve to get the answer

$\frac {1200000}{3.33}=360.\overline {360}$

$\frac {360.\overline {360}}{2 * 0.06 * \pi}=955855.544095467482$

When you round this quotient to the nearest thousand you get 956000.

Bits per meter of a CD

The answer is 956000.

2 solutions

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