Math Problem Statement

  1. For a violin, estimate the length of the portions of the strings that are free to vibrate. (a) The frequency of the note played by the open E5 string vibraing in its fundamental standing wave is 659 Hz. Use your estimate of the length to calculate the wave speed for the transverse waves on the string.

Solution

To estimate the length of the vibrating portion of the string and calculate the wave speed, we'll break the problem down into manageable steps.

Step 1: Estimate the length of the vibrating portion of the string

For a violin, the vibrating portion of the string refers to the length of the string between the bridge and the nut. The typical length of this vibrating portion on a violin is about 32 cm (0.32 m), though it can vary slightly depending on the violin. We’ll use this as a reasonable estimate for the length of the vibrating portion of the string.

Step 2: Relate frequency to wave speed

The fundamental frequency of the vibrating string is related to the wave speed vv, the string's length LL, and the frequency ff by the following relationship for the fundamental mode of vibration:

f=v2Lf = \frac{v}{2L}

where:

  • ff is the frequency of the wave (659 Hz for the open E5 string),
  • LL is the length of the vibrating portion of the string (0.32 m),
  • vv is the wave speed on the string, which we need to calculate.

Rearranging the formula to solve for vv:

v=2L×fv = 2L \times f

Substitute the known values:

v=2×0.32m×659Hzv = 2 \times 0.32 \, \text{m} \times 659 \, \text{Hz}

v=2×0.32×659=421.12m/sv = 2 \times 0.32 \times 659 = 421.12 \, \text{m/s}

Step 3: Conclusion

The estimated wave speed on the string for the E5 note vibrating in its fundamental mode is approximately 421 m/s.

Would you like further details on this calculation, or do you have any questions? Here are some related topics you might be interested in:

  1. How does the tension in the string affect the wave speed?
  2. How does changing the frequency of the string affect its vibration and wave speed?
  3. How can the length of a string on a violin be adjusted to tune it to a specific note?
  4. What other factors influence the wave speed on a violin string besides tension and length?
  5. How does the wave speed relate to the harmonics and overtones of the vibrating string?

Tip: The wave speed vv is directly proportional to the square root of the tension TT and inversely proportional to the square root of the mass per unit length μμ of the string: v=T/μv = \sqrt{T/\mu}.

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Math Problem Analysis

Mathematical Concepts

Wave Speed
Fundamental Frequency
Vibrating Strings
Physics of Sound

Formulas

f = v / (2L)
v = 2L * f

Theorems

Wave Equation for Vibrating Strings

Suitable Grade Level

Grades 10-12