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Homework Help: Waves and Sounds - speed of a bat

  1. Jan 29, 2009 #1
    1. The problem statement, all variables and given/known data

    A bat moving at 4.5 m/s is chasing a flying insect insect. The bat emits a 52 kHz chirp and receives back an echo at 52.75 kHz. At what speed is the bat gaining on its prey? Take the speed of sound in air to be 342 m/s.

    2. Relevant equations

    f1 = f ((velocity +/- velocity observer)/(velocity +/- velocity source))

    3. The attempt at a solution

    To start off, I converted 52 kHz to 52,000 Hz and 52.75 kHz

    Then my equation looked like:

    52750 = 52000 ((342 - vo)/(342-4.5)

    I found vo to be .367788 and subtracted that from 4.5 to find the speed gained, but that doesn't seem to work. Can anyone help?
  2. jcsd
  3. Jan 29, 2009 #2
    Can anybody help me out?
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