Tripling fundamental frequency

[Strbarrytree]

So the question goes like this- The fundamental frequency of a bass violin string is 1045 Hz and occurs when the string is 0.900 m long. How far from the lower fixed end of the bass violin should you place your fingers to allow the string to vibrate at a fundamental frequency 3 times as great?

I say you take (2*.9)*1045 to get 1881 m/s because of v=f*w, then you take (1881/(1045*3))/2 to get .3 because of f=v/2l, and .3 would be the answer which would make sense since .3=(1/3).9

My teacher who is a smart man says you would disregard the information you got about the length of the string (the 0.900 m) and just take (340(speed of sound in air)/(3*1045))/2 or something like that he got like .84 or .084 which doesn't add up to the equation I just said, but that's what he said to do because he said it has to travel through air so we can hear it.

I think that that is irrelevant because it is not asking for how we perceive the frequency but rather what the string is actually doing. So I just kinda want an answer to know whose right so if this is on my text I know what to do. Thank you

 

[Delphi51]

I agree with you. Nothing to do with air.

 

[tomcue]

I would say that both approaches have some validity, but it ultimately depends on the context and purpose of the question. If the question is asking for the physical placement of the fingers on the string to achieve a particular fundamental frequency, then your approach is correct. However, if the question is asking for the actual perceived frequency of the sound, then your teacher's approach is more appropriate as it takes into account the speed of sound in air. Both approaches are valid and can be used depending on the specific context of the question. It is important to consider all factors and not just focus on one aspect when solving scientific problems.