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Ch 26: Sound Calculations
Problems – Show your work and the answer with correct units
1) Most people can detect frequencies as high as 20 000 Hz. Assuming the speed of sound in air is 345 m/s, determine
the wavelength of the sound corresponding to this upper range of audible hearing.
2) An owl’s hoot travels through the air with a speed of 330 m/s. If you hear the hoot a distance of 400 m away, how long
did it take for the hoot to reach you?
3) Determine the speed of sound on a cold winter day (T=3 degrees C). Use V = 331 m/s + (0.6 m/s/C) • T
4) An oceanic depth sounding vessel surveys the ocean bottom with ultrasonic sound that travels 1530 m/s in seawater.
Find the depth of the water if the time of delay of the echo to ocean floor and back is 8 seconds.
5) A crack a thunder is heard 10 seconds after you see lightning, if the speed of sound is 340 m/s, how far away is the
lightning?
6) A monkey’s screech produces a sound wave in room temperature air that has a wavelength of 1m, what would its
frequency need to be?
7) Dan and his friends are in a canyon and his echo is heard 1.40 seconds after making the holler, what is the distance to
the canyon wall?
8) The frequency of a certain tuning fork is 420 Hz. In room temperature air, what is the wavelength of sound coming from
the fork?
9) Humpback whales are known to produce a collection of elaborate and repeating sounds with frequencies ranging from
20 Hz to 10 kHz. The sound waves travel through water at speeds of approximately 1400 m/s. Determine the
wavelengths of the waves at the lower and the upper end of this frequency range.
10) If the speed of sound at 0˚C is 330 m/s. how fast will it travel at 5˚C?
11) An automatic focus camera is able to focus on objects by use of an ultrasonic sound wave. The camera sends out
sound waves that reflect off distant objects and return to the camera. A sensor detects the time it takes for the waves to
return and then determines the distance an object is from the camera. If a sound wave (speed = 340 m/s) returns to the
12) Find the wavelength of the ultrasonic wave emitted by a bat if it has a frequency of 4.0 x 104 Hz.
13) Emma is rock'n to her favorite radio station - 102.3 FM. The station broadcasts radio signals with a frequency of 1.023 x
108 Hz. The radio wave signal travel through the air at a speed of 2.997 x 108 m/s. Determine the wavelength of these
radio waves.
14) Aron blows across the opening of a partially filled 20.0 cm high soft drink bottle and finds that the air vibrates with a
fundamental frequency of 472 Hz. How high is the liquid in the bottle?
15) On a hot summer day, a pesky little mosquito produced its warning sound near your ear. The sound is produced by the
beating of its wings at a rate of about 600 wing beats per second.
a. What is the frequency in Hertz of the sound wave?
b. Assuming the sound wave moves with a velocity of 350 m/s, what is the wavelength of the wave?
16) Melody puts a fret on her guitar string, causing it to vibrate with a fundamental frequency of 250 Hz as a wave travels
through at 350 m/s.
a. How long is the guitar string from the lower fixed end to the fret?
b. How far and in which direction must the fret be moved in order to produce a fundamental frequency that is
twice as high (one octave higher)?
17) Miles Tugo is camping in Glacier National Park. In the midst of a glacier canyon, he makes a loud holler. He hears an
echo 1.22 seconds later. The air temperature is 20 degrees C. How far away are the canyon walls?
18) A piano tuner from Chicago is tuning the Bentz’ piano when he discovers that the G above middle C is vibrating with a
higher frequency than his G tuning fork, which vibrates at 392.0 Hz. He plays the piano key and tuning fork at the same
time and hears a beat frequency of 2.0 Hz. What is the frequency of the G on the Bentz’ piano?
19) A tuning fork with a frequency of 440 Hz is played simultaneously with a fork with a frequency of 437 Hz. How many
beats will be heard over a period of 10 seconds?