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Q. 75

Expert-verified
Found in: Page 454

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# An avant-garde composer wants to use the Doppler effect in his new opera. As the soprano sings, he wants a large bat to fly toward her from the back of the stage. The bat will be outfitted with a microphone to pick up the singer’s voice and a loudspeaker to rebroadcast the sound toward the audience. The composer wants the sound the audience hears from the bat to be, in musical terms, one half-step higher in frequency than the note they are hearing from the singer. Two notes a half-step apart have a frequency ratio of 21/12 = 1.059. With what speed must the bat fly toward the singer?

The speed of the bat is 9.74 m/s

See the step by step solution

## Step 1: Write the given information

The frequency ratio of two notes is 21/12 = 1.059

The speed of the sound is vs = 340 m/s

Let the speed of the bat is vb

## Step 2: To determine the speed of the bat

The frequency reflected by the bat is given by

Here, f= frequency of the sound source

vs = speed of the soundvb= speed of the bat

According to the statement given,

Substitute the known values,

Thus, the speed of the bat is 9.74 m/s