/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 A bass guitar string is 89 cm lo... [FREE SOLUTION] | 91Ó°ÊÓ

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A bass guitar string is 89 cm long with a fundamental frequency of \(30 \mathrm{Hz}\). What is the wave speed on this string?

Short Answer

Expert verified
The wave speed on this string is 53.4 m/s.

Step by step solution

01

Identify the given values

The length of the string \(L\) is given as 89 cm and the fundamental frequency \(f\) is given as 30 Hz.
02

Find the wavelength

For a string that is fixed at both ends, the wavelength \(\lambda\) of the fundamental frequency (also known as the first harmonic) is twice the length of the string. Therefore, we calculate \(\lambda = 2L = 2 \times 89 \, cm = 178 \, cm = 1.78 \, m\). We convert the length into meters because the standard unit of wavelength is meters.
03

Calculate the speed of the wave

Now we have the frequency and the wavelength, we substitute those into the formula for the speed of a wave: \(v = f \cdot \lambda = 30 \, Hz \times 1.78 \, m = 53.4 \, m/s\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Fundamental Frequency
Imagine gently plucking a bass guitar string and hearing the lowest pitch that the string can produce; this is what we call the fundamental frequency . It's the musical tone produced by the string when it vibrates at its simplest possible form, essentially at its most basic state. It's significant because the fundamental frequency sets the precedent for all other harmonics , which are higher pitched tones that resonate at multiples of the fundamental.

When you're working with a string instrument like a bass guitar, this fundamental frequency is determined by various factors, including string length, tension, and density. In the case of our exercise, the given fundamental frequency is 30 Hz, which means the string vibrates 30 times every second when playing this most basic tone. Understanding this concept is crucial when you start diving into the world of acoustics and string instruments.
Wavelength Calculation
When it comes to wave speed on a string, knowing how to calculate the wavelength is crucial. The wavelength is the distance between consecutive points of the wave in one cycle, or simply put, it's the length of one complete wave. Interestingly, for a string fixed at both ends—like a guitar or bass string—the wavelength of the fundamental frequency is twice the length of the string itself, because the two fixed points serve as nodes where the wave doesn't move.

In our example, where the string measures 89 cm, the wavelength for the fundamental is calculated as 178 cm, or 1.78 meters when we need it in standard units. Being familiar with this calculation is useful not just for solving textbook exercises, but also for understanding the physical properties of musical instruments and sound waves.
Harmonics
Now let's explore the concept of harmonics . While the fundamental frequency gives the basic note, harmonics, or overtones , are the additional frequencies that the string can generate and are integral to the rich sound we associate with stringed instruments. These harmonics are actually whole number multiples of the fundamental frequency. If the fundamental frequency is like the first 'layer' of a sound, harmonics are the subsequent layers that add complexity and richness.

For example, if a string's fundamental frequency is 30 Hz, the second harmonic would be 60 Hz, the third would be 90 Hz, and so on. Each harmonic frequency has its own wavelength and mode of vibration on the string, and understanding these can lead to a deeper appreciation and technical grasp of how musical instruments work. In the context of our problem-solving, grasping the relationship between the fundamental frequency and the harmonics aids in a comprehensive understanding of wave behavior on strings.

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Most popular questions from this chapter

The speed of sound in room temperature \(\left(20^{\circ} \mathrm{C}\right)\) air is \(343 \mathrm{m} / \mathrm{s} ;\) in room temperature helium, it is \(1010 \mathrm{m} / \mathrm{s} .\) The fundamental frequency of an open-closed tube is 315 Hz when the tube is filled with air. What is the fundamental frequency if the air is replaced with helium?

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In noisy factory environments, it's possible to use a loudspeaker to cancel persistent low-frequency machine noise at the position of one worker. The details of practical systems are complex, but we can present a simple example that gives you the idea. Suppose a machine \(5.0 \mathrm{m}\) away from a worker emits a persistent \(80 \mathrm{Hz}\) hum. To cancel the sound at the worker's location with a speaker that exactly duplicates the machine's hum, how far from the worker should the speaker be placed? Assume a sound speed of \(340 \mathrm{m} / \mathrm{s}\).

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Musicians can use beats to tune their instruments. One flute is properly tuned and plays the musical note A at exactly \(440 \mathrm{Hz}\). A second player sounds the same note and hears that her instrument is slightly "flat" (that is, at too low a frequency). Playing at the same time as the first flute, she hears two loud-soft-loud beats per second. What is the frequency of her instrument?

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