Hi, this is the question:(adsbygoogle = window.adsbygoogle || []).push({});

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A bat flies toward a wall, emitting a steady sound with a frequency of 22.5 kHz. This bat hears its own sound plus the sound reflected by the wall.

How fast should the bat fly, v_b, to hear a beat frequency of 225 Hz?

Take the speed of sound to be 344m/s.

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This is what I've done so far:

I've found the frequency that the bat hear when it echoes off the wall. I

got the equation... Fbat = Fo ((v_w + v_b) / (v_w - v_b)) where Fbat is

the frequency that the bat will here off of the wall, Fo is the original

emittance frequency from the beginning, and v_b is the velocity the bat

should be traveling in.

I've then solved for v_b... rearranging the formula. But from there, I'm not too sure how to incorporate the "beats" idea.

I also believe the beat frequency formula is f_beat = f_1 - f_2 = 225 Hz.

As far as this problem goes, that's all I know how to do - I'm stuck at

this point. Could you help me out?

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# Homework Help: Bat echolocation - doppler effect

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