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5 parts
a

200 m/s200 \text{ m/s}

b

1.32 m1.32 \text{ m}

151.52 Hz151.52 \text{ Hz}

c

21%21\%

e

10−2 W/m210^{-2} \text{ W/m}^2

f

2.243 m2.243 \text{ m}

Step-by-step solution

12 steps

Here is the solution for ITEM 3, presented in English:

This problem involves calculating the speed, fundamental frequency, and wavelength of a transverse wave on a stretched string, along with concepts of sound intensity.

Given values:

  • String length, L=0.66 mL = 0.66 \text{ m}
  • Tension in the string, T=160 NT = 160 \text{ N}
  • Mass per unit length, μ=4.0×10−3 kg/m\mu = 4.0 \times 10^{-3} \text{ kg/m}
  • Speed of sound in air, Vsound=340 m/sV_{sound} = 340 \text{ m/s}

Part a· 2 steps

Calculate the speed of transverse wave along the stretched string.

  1. Use the formula for the speed of a transverse wave on a string.

    The speed VV of a transverse wave on a stretched string is given by:

    V=TμV = \sqrt{\frac{T}{\mu}}
  2. Substitute the given values into the formula and calculate VV.

    V=160 N4.0×10−3 kg/mV = \sqrt{\frac{160 \text{ N}}{4.0 \times 10^{-3} \text{ kg/m}}} V=40000 m/sV = \sqrt{40000} \text{ m/s} V=200 m/sV = 200 \text{ m/s}

    The speed of the transverse wave is 200 m/s\boxed{200 \text{ m/s}}.

Part b

1.32 m1.32 \text{ m}

Calculate the fundamental frequency and wavelength of the stationary wave produced on the string.

  1. Calculate the wavelength for the fundamental mode (first harmonic).

    For a string fixed at both ends, the fundamental wavelength (λ1\lambda_1) is twice the length of the string:

    λ1=2L\lambda_1 = 2L λ1=2×0.66 m\lambda_1 = 2 \times 0.66 \text{ m} λ1=1.32 m\lambda_1 = 1.32 \text{ m}

    The fundamental wavelength is 1.32 m\boxed{1.32 \text{ m}}.

  2. Calculate the fundamental frequency.

    The fundamental frequency (f1f_1) is related to the wave speed VV and fundamental wavelength λ1\lambda_1 by the formula f1=Vλ1f_1 = \frac{V}{\lambda_1}:

    f1=200 m/s1.32 mf_1 = \frac{200 \text{ m/s}}{1.32 \text{ m}} f1≈151.52 Hzf_1 \approx 151.52 \text{ Hz}

    The fundamental frequency is 151.52 Hz\boxed{151.52 \text{ Hz}}.

Part c

21%21\%

Determine by what percentage the tension T must be increased to raise the fundamental pitch of the string by 10%.

  1. Write the relationship between fundamental frequency and tension.

    The fundamental frequency (f1f_1) of a wave on a string is given by the formula:

    f1=12LTμf_1 = \frac{1}{2L}\sqrt{\frac{T}{\mu}}

    From this, we see that f1f_1 is directly proportional to the square root of the tension: f1∝Tf_1 \propto \sqrt{T}.

  2. Find the relationship for the new tension.

    If the fundamental frequency is increased by 10%, the new frequency f1′f_1' will be 1.10f11.10 f_1.
    Thus, we can write:

    f1′f1=1.10f1f1=1.10\frac{f_1'}{f_1} = \frac{1.10 f_1}{f_1} = 1.10

    Using the proportionality f1∝Tf_1 \propto \sqrt{T}:

    f1′f1=T′T\frac{f_1'}{f_1} = \sqrt{\frac{T'}{T}}

    Where T′T' is the new tension.

    1.10=T′T1.10 = \sqrt{\frac{T'}{T}}
  3. Calculate the percentage increase in tension.

    Square both sides:

    (1.10)2=T′T(1.10)^2 = \frac{T'}{T} 1.21=T′T1.21 = \frac{T'}{T}

    This means T′=1.21TT' = 1.21 T.
    The percentage increase in tension is:

    Percentage increase=T′−TT×100%\text{Percentage increase} = \frac{T' - T}{T} \times 100\% =1.21T−TT×100%= \frac{1.21T - T}{T} \times 100\% =0.21TT×100%= \frac{0.21T}{T} \times 100\% =0.21×100%=21%= 0.21 \times 100\% = 21\%

    The tension must be increased by 21%\boxed{21\%}.

Part d

Define sound intensity (I) and sound intensity level (B).

  • Sound intensity (I): This is the amount of sound energy passing per unit time through a unit area that is perpendicular to the direction of sound wave propagation. It is measured in Watts per square meter (W/m2\text{W/m}^2).

  • Sound intensity level (B): This is a logarithmic measure of the sound intensity relative to a reference intensity, which is typically the threshold of human hearing. It is measured in decibels (dB).

Part e

10−2 W/m210^{-2} \text{ W/m}^2

Calculate the sound intensity I in W/m² corresponding to the 100 dB measurement.

  1. Use the formula for sound intensity level.

    The formula for sound intensity level (BB) is:

    B=10log⁡10(II0)B = 10 \log_{10}\left(\frac{I}{I_0}\right)

    Where II is the sound intensity, and I0I_0 is the reference intensity, which is 10−12 W/m210^{-12} \text{ W/m}^2.

  2. Substitute the given values and solve for II.

    We are given B=100 dBB = 100 \text{ dB}.

    100=10log⁡10(I10−12)100 = 10 \log_{10}\left(\frac{I}{10^{-12}}\right)

    Divide both sides by 10:

    10=log⁡10(I10−12)10 = \log_{10}\left(\frac{I}{10^{-12}}\right)

    To remove the logarithm, raise both sides to the power of 10:

    1010=I10−1210^{10} = \frac{I}{10^{-12}}

    Solve for II:

    I=1010×10−12I = 10^{10} \times 10^{-12} I=10(10−12)I = 10^{(10-12)} I=10−2 W/m2I = 10^{-2} \text{ W/m}^2

    The sound intensity is 10−2 W/m2\boxed{10^{-2} \text{ W/m}^2}.

Part f

2.243 m2.243 \text{ m}

Calculate the wavelength of emitted sound wave.

  1. Identify the given values and the necessary frequency.

    The speed of sound in air is 340 m/s340 \text{ m/s}. We assume the emitted sound wave has the same frequency as the fundamental frequency of the string, which was calculated in part b) as f1≈151.52 Hzf_1 \approx 151.52 \text{ Hz}.
    Given:
    Speed of sound in air, Vsound=340 m/sV_{sound} = 340 \text{ m/s}
    Frequency of emitted sound, f=151.52 Hzf = 151.52 \text{ Hz}

  2. Use the wave speed formula to calculate the wavelength.

    The relationship between wave speed (VV), frequency (ff), and wavelength (λ\lambda) is V=fλV = f\lambda.
    Rearranging for wavelength:

    λ=Vf\lambda = \frac{V}{f}
  3. Substitute the values and calculate the wavelength.

    λ=340 m/s151.52 Hz\lambda = \frac{340 \text{ m/s}}{151.52 \text{ Hz}} λ≈2.243 m\lambda \approx 2.243 \text{ m}

    The wavelength of the emitted sound wave is 2.243 m\boxed{2.243 \text{ m}}.

Part g

Calculate the maximum

This part of the question is incomplete as the quantity to be maximized is not specified. Therefore, it cannot be solved.

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