Concept explainers
BIO Horseshoe bats (genus Rhinolophus) emit sounds from their nostrils and then listen to the frequency of the sound reflected from their prey to determine the prey’s speed. (The “horseshoe” that gives the bat its name is a depression around the nostrils that acts like a focusing mirror, so that the bat emits sound in a narrow beam like a flashlight.) A Rhinolophus flying at speed υbat emits sound of frequency fbat; the sound it hears reflected from an insect flying toward it has a higher frequency frefl. (a) Show that the speed of the insect is
where υ is the speed of sound. (b) If fbat = 80.7 kHz, frefl = 83.5 kHz. and υbat = 3.9 m/s, calculate the speed of the insect.
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