ICQ$21.(40$ points$)$ CH$.12$ An outside stereo speaker at a ski resort emits sound waves with a power output of $90\mathrm{.}00$ W and frequency $1000\mathrm{.}00$ Hz $.$

A$.(10$ points$)$ At what distance from the speaker would you experience the sound at exactly $111$ dB $?$

DOPPLER EFFECT

B$.(10$ points$)$ Suppose a skier is traveling toward the speaker at speed $19\mathrm{.}72\frac{m}{s}.$ What is the frequency heard by the skier?

C$.(10$ points$)$ Suppose a skier is traveling away fromthe speaker at speed $19\mathrm{.}65\frac{m}{s}.$ What is the frequency heard by the skier?

D$.(10$ points$)$ Compare the wavelengths of part $b.$ and part $c.$ Which wavelength is larger, that of part $b.$ or part $c?$ Compute the magnitude of the difference between the wavelengths in part $b.$ and part $c.$