Question about transverse standing wave including violin string

[pinal08854]

I have a question on this problem
1. 10. A violin string vibrates at 335 Hz when unfingered. At what frequency will it vibrate if it is fingered one half of the way down from the end?

For this one I worked out that string is fixed at both ends because its in a violin so I am thinking of using f=n v/2L where L=1 lambda/2 and v= lambda f. So overall it comes out to be f= nf, so in this case the n would be 1, right so the answer would be the same...right?
I don't know if this is the right approach but this is what I am thinkin...any suggestions might help me figure out this problem..
Thanks!

 

[Kurdt]

The 'fingered' reference refers to actually holding the string down at its midway point making the string half the length of the unfingered or open position. It is not a reference to plucking half way down the string as I believe you have taken it to be.

 

[arunbg]

Yes, I agree with Kurdt .
Also note that at the point of fingering , there exists a node .
What is the value of n then ?

 

[pinal08854]

so that means the value of n would be 1/2, right? because it's fingered half way through the wave. Wouldn't n be a whole number..I really have no idea

 

[Kurdt]

The string becomes fixed at a new position (i.e. L/2) so find the frequency of the string with this length instead of the old.

 

[pinal08854]

so basically the new frequency is half of original one which would be 167.5 Hz, right? because if I substitute this in place of L I get f= n f/2 which comes out to be 335/2= 167.5...right? Am I making sense?

 

[Kurdt]

I think your algebra is a little out it should be double but I'll leave it to you to try and find your mistake. If you still have trouble don't hesitate to post again.

 

[arunbg]

Yes, it should be double.
Can you physically "see" why the frequency increases ?
As suggested you have made some algebraic error .
_______________________________________________

Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.
Albert Einstein

 

[pinal08854]

You guys are right...I made a stupid algebraic mistake and figured it out to be 670 Hz instead of 167.5 Hz. I plugged in L/2 in the wrong place...stupid substitution error...Thanks a lot for helping me, guys.