Is my solution right or wrong ?

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The discussion revolves around a physics problem involving a copper wire, a pulley, and the calculation of the lowest frequency for stationary waves. The provided solution calculates the pressure in the wire, the wave velocity, and ultimately derives the frequency to be approximately 10 Hz. The approach treats the system as an air column with one end closed, aligning the wavelength with the length of the wire. Key calculations include tension, mass per unit length, and the relationship between wave velocity and frequency. The solution effectively demonstrates the principles of wave mechanics in a practical scenario.
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My question follow with my work to solve the question is in the attachment .
 

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Sanosuke Sagara said:
My question follow with my work to solve the question is in the attachment .

"Selected zip file is invalid or corrupted"
 
Don't worry

don't worry, the file will not harm your computer.Just zip it and mu solution is in there.
 
The file contains a windows excel document with a picture:

There a string (copper wire?) attached to an oscillilator at one end (point A). The other end of the string is hung over a pulley (point B) and a mass tied to the end of the string.
The problem is:
The length AB of the copper wire (the dot line) used in this experiment is 1.5m and its cross sectional area is 0.059mm^2
The tension in the wire is 2.0 N. If the density of the copper is 8.9 x 10^3 kg/m^3 ,show that the lowest frequency to obtain a stationary wave is about 10Hz.

Sanosuke's solution is:
Pressure P=\frac{2}{0.059\cdot 10^{-6}}=33898305 Pa
V=\sqrt{\frac{33898305}{8.9 \cdot 10^3}}=61.72 m/s

V=fl (l is wavelength)

f=\frac{V}{l}=\frac{V}{4 \cdot 1.5}=\frac{61.72}{6}=10.3 Hz \approx 10 Hz
 
Last edited:
Can I conceive the system to be an air column with one end closed as the l(wavelength) is equal to 4L ?

By this way, I can obtain the answer to be at least 10Hz.
 
Here treat it as a rope with both ends tied to a wall.

The Mass is given so that the tension in the rope "T=Mg" can be found
Also the mass per unit length \mu can be found using the given data

then the velocity of the wave in the string will be
v= \sqrt \frac{T}{ \mu}

Using the velocity and the fact that the wavelength will correspond to
\frac{n \lambda}{2}
The frequency can be found
 
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