Help with a physics sound problem.

In summary, two identical strings tuned to the 440-Hz A note have a beat frequency of 3.3Hz when one string's tension is decreased by 1.5%. The velocity of the wave on a tensioned string is the key factor in determining the pitch and wavelength.
  • #1
maninthesuit
2
0
1. Two identical strings on different cellos are tuned to the 440-Hz A note. The peg holding one of the strings slips, so its tension is decreased by 1.5%. What is the beat frequency heard when the strings are played together?
f₁=440Hz; Tension decrease=1.5%2. f(beat)=|f₁-f₂|3.
f₂=440Hz - (440Hz*.015)=433.4Hz
f(beat)=|440Hz-433.4Hz|=6.6Hz

The answer is supposed to be 3.3Hz. I would really appreciate the help. Thanks.
 
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  • #2
I think you're missing a key formula here.
Remember that the velocity of the wave on a tensioned string is

v = √(F / µ) where µ is the string density. Use it more conceptually now, and think about the relationship of the force to the velocity, and the velocity to the pitch and wavelength.
 
  • #3
Thank you very much. I got the right answer now. Much appreciated. :)
 

Related to Help with a physics sound problem.

1. What is the definition of sound in physics?

Sound in physics is defined as a form of energy that is transmitted through vibrations or waves in a medium such as air, water, or solids. It is a mechanical wave that travels through these mediums and can be detected by the human ear.

2. How is sound measured in physics?

In physics, sound is measured in units of frequency, amplitude, and intensity. Frequency is measured in Hertz (Hz) and represents the number of vibrations per second. Amplitude is measured in decibels (dB) and represents the loudness or strength of the sound wave. Intensity is measured in Watts per square meter (W/m2) and represents the amount of energy carried by the sound wave.

3. What is the speed of sound in different mediums?

The speed of sound varies depending on the medium it travels through. In air, the speed of sound is approximately 343 meters per second. In water, the speed of sound is about 1,500 meters per second, and in solids, the speed can reach up to 5,000 meters per second.

4. How does temperature affect the speed of sound?

The speed of sound is directly affected by temperature. As the temperature increases, the speed of sound also increases. This is because the molecules in the medium have more thermal energy, causing them to vibrate faster and transmit the sound waves more quickly.

5. What is the Doppler effect in relation to sound?

The Doppler effect is a phenomenon that occurs when there is relative motion between a source of sound and an observer. It causes a change in the frequency of the sound perceived by the observer. When the source is moving towards the observer, the frequency appears higher, and when the source is moving away, the frequency appears lower.

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