4. A bat is flying at 2.550% of the speed of sound toward another bat that is hanging in a cave. The hanging bat emits a sound of frequency 3.900 kHz. (a) What is the frequency the flying bat hears? (b) If the sound level is 100 dB at 10 cm from the hanging bat, what is the sound level heard by the flying bat when it is 10 m away?

4. A bat is flying at 2.550% of the speed of sound toward another bat that is hanging in a cave. The hanging bat emits a sound of frequency 3.900 kHz. (a) What is the frequency the flying bat hears? (b) If the sound level is 100 dB at 10 cm from the hanging bat, what is the sound level heard by the flying bat when it is 10 m away?

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter14: Superposition And Standing Waves

Section: Chapter Questions

Problem 1OQ: A flute has a length of 58.0 cm. If the speed of sound in air is 343 m/s, what is the fundamental...

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A family ice show is held at an enclosed arena. The skaters perform to music with level 80.0 dB. This level is too loud for your baby, who yells at 75.0 dB. (a) What total sound intensity engulfs you? (b) What is the combined sound level?
A flute has a length of 58.0 cm. If the speed of sound in air is 343 m/s, what is the fundamental frequency of the flute, assuming it is a tube closed at one end and open at the other? (a) 148 Hz (b) 296 Hz (c) 444 Hz (d) 591 Hz (e) none of those answers
Based on the graph in Figure 17.36, what is the threshold of hearing in decibels for frequencies of 60, 400, 1000, 4000, and 15,000 Hz? Note that many AC electrical appliances produce 60 Hz, music is commonly 400 Hz, a reference frequency is 1000 Hz, your maximum sensitivity is near 4000 Hz, and many older TVs produce a 15,750 Hz whine. Figure 17.36 The relationship of loudness in phons to intensity level (in decibels) and intensity (in watts per meter squared) for persons with normal hearing. The curved lines are equal-loudness curves—all sounds on a given curve are perceived as equally loud. Phons and decibels are defined to be the same at 1000 Hz.
The area of a typical eardrum is about 5.00 X 10-5 m2. (a) (Calculate the average sound power incident on an eardrum at the threshold of pain, which corresponds to an intensity of 1.00 W/m2. (b) How much energy is transferred to the eardrum exposed to this sound lor 1.00 mill?
Write an expression that describes the pressure variation as a function of position and time for a sinusoidal sound wave in air. Assume the speed of sound is 343 m/s, = 0.100 m, and Pmax = 0.200 Pa.
An outside loudspeaker (considered a small source) emits sound waves with a power output of 100 W. (a) Find the intensity 10.0 m from the source. (b) Find the intensity level in decibels at that distance. (c) At what distance would you experience the sound at the threshold of pain, 120 dB?
The most soaring vocal melody is in Johann Sebastian Bach's Mass in B Minor. In one section, the basses, tenors. altos, and sopranos carry the melody from a low D to a high A. In concert pitch, these notes are now assigned frequencies of l 46.8 Hz and 880.0 Hz. Find the wave lengths of (a) the initial note and (b) the final note. Assume the chorus sings the melody with a uniform sound level of 75.0 dB. Find the pressure amplitudes of (c) the initial note and (d) the final note. Find the displacement amplitudes of (e) the initial note and (f) the final note.
As you travel down the highway in your car, an ambulance approaches you from the rear at a high speed (Fig. OQ17.3) sounding its siren at a frequency of 500 Hz. Which statement is correct? (a) You hear a frequency less than 500 Hz. (b) You hear a frequency equal to 500 Hz. (c) You hear a frequency greater than 500 Hz. (d) You hear a frequency greater than 500 Hz. whereas the ambulance driver hears a frequency lower than 500 Hz. (e) You hear a frequency less than 500 Hz. whereas (he ambulance driver hears a frequency of 500 Hz.
A tuning fork is known to vibrate with frequency 262 Hz. When it is sounded along with a mandolin siring, four beats are heard every second. Next, a bit of tape is put onto each line of the tuning fork, and the tuning fork now produces five beats per second with the same mandolin siring. What is the frequency of the string? (a) 257 Hz (b) 258 Hz (c) 262 Hz (d) 266 Hz (e) 267 Hz
A crude approximation at voice production is to consider the breathing passages and mouth to be a resonating tube closed at one end. (See Figure 17.30.) (a) What is the fundamental frequency if the tube is 0.240-m long, by taking air temperature to be 37.0°C? (b) What would this frequency become it the person replaced the air with helium? Assume the same temperature dependence for helium as for air. Figure 17.30 The throat and mouth form an air column closed at one end that resonates in response to vibrations in the voice box. The spectrum of overtones and their intensities vary with mouth shaping and tongue position to form different sounds. The voice box can be replaced with a mechanical vibrator, and understandable speech is still possible. Variations in basic shapes make different voices recognizable.