# Homework Help: Sound & Music - Tension of a string

Tags:
1. Apr 24, 2017

### Torrie

1. The problem statement, all variables and given/known data

1. The A string on a violin has a fundamental frequency of 440Hz. The length of the vibrating portion is 32.4cm and has a mass of 0.340g. Under what tension must the string be placed?

2. Relevant equations
V = Fλ
Vs = √t/μ

3. The attempt at a solution
I plugged in my info to determine V = 142.604
then I attempted the second equation as:
T = .340(142.604^2)
This gave me the wrong answer
I also tried:
T = 1.049(142.604^2) - (.340g/.324m = 1.049g/m)
This also gave me the wrong answer. I am not sure what to do

2. Apr 24, 2017

### Torrie

Now I realize that v = 285.12. I forgot to multiple length by 2 to get the wavelength.
But I still can't figure out the second equation

3. Apr 25, 2017

### Staff: Mentor

Make sure that your units all match (pay attention to your units for μ).

4. Apr 25, 2017

### Torrie

Should μ be kg/m?
So... 0.00034/.324m = .001049kg/m?

5. Apr 25, 2017

### Staff: Mentor

Yes.

6. Apr 25, 2017

### Torrie

Okay so then I have

.001049(285.12^2) = 85.277

So the tension would need to be 85.277N?

7. Apr 25, 2017

### Staff: Mentor

Looks right to me. Be sure to round to the required number of significant figures.

8. Apr 25, 2017

### Torrie

Thank you so much!