P16_010.PDF

10. (a) The problem gives the frequency f = 440 Hz, where the SI unit abbreviation Hz stands for Hertz,

which means a cycle-per-second. The angular frequency ω is similar to frequency except that ω

is in radians-per-second. Recalling that 2 π radians are equivalent to a cycle, we have ω =2 πf

2800 rad/s.

(b) In the discussion immediatelyafter Eq. 16-6, the book introduces the velocity amplitude v m = ωx m .

With x m =0 . 00075 m and the above value for ω , this expression yields v m =2 . 1m/s.

ω 2 x m , which (if the more precise value ω = 2765 rad/s is used) yields a m =5 . 7km/s.

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