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Ch 16: Traveling Waves
Chapter 16, Problem 17

FIGURE EX17.6 shows a standing wave oscillating at 100 Hz on a string. What is the wave speed? Diagram of a standing wave on a string, oscillating at 100 Hz, with a length of 72 cm.

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Identify the given information: the frequency of the standing wave is 100 Hz and the length of the string is 72 cm.
Count the number of wavelengths in the standing wave. From the image, there are 3 complete wavelengths.
Calculate the wavelength (λ) by dividing the length of the string by the number of wavelengths. λ = 72 cm / 3.
Convert the wavelength from cm to meters if necessary.
Use the wave speed formula v = f * λ, where f is the frequency and λ is the wavelength, to find the wave speed.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Wave Speed

Wave speed is the distance a wave travels per unit of time. It can be calculated using the formula v = fλ, where v is the wave speed, f is the frequency, and λ (lambda) is the wavelength. In this case, the frequency is given as 100 Hz, and the wavelength can be determined from the standing wave pattern shown in the figure.
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Standing Waves

A standing wave is formed when two waves of the same frequency and amplitude travel in opposite directions and interfere with each other. This results in nodes (points of no displacement) and antinodes (points of maximum displacement) along the medium. The length of the string and the number of wavelengths it contains are crucial for determining the wavelength in this scenario.
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Wavelength

Wavelength is the distance between successive crests (or troughs) of a wave. For standing waves, the wavelength can be calculated based on the length of the string and the number of loops formed. In this case, the string length of 72 cm can be used to find the wavelength, which is essential for calculating the wave speed.
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