# Homework Help: Fundamental Frequency.

1. Dec 8, 2013

### i'mcheche

1. The problem statement, all variables and given/known data
a flexible wire is 80 cm long has a mass of 0.40g. It is stretched across stops on a sonometer that are 50 cm apart by a force of 500N. Find the fundamental frequency with which the wire may vibrate. If it vibrates in 2 third overtone, what is it's frequency?

2. Relevant equations
$$f=\frac{1}{2L}\sqrt{\frac{T}{\frac{m}{L}}}$$

3. The attempt at a solution
I don't kno where to start. I substituted all the given data. And i'm not really sure about my answer.

I can't decide what length should be used in the equation. the problem states the total length of the wire and the length of the wire which is streched on the sonometer.

Last edited: Dec 8, 2013
2. Dec 8, 2013

### nil1996

welcome to PF

it is said that the sonometer stops are 50cm apart.So that should me the length.

3. Dec 9, 2013

### Staff: Mentor

There are two L's in the equation. Are they necessarily the same?

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