A string that is 6m long is vibrating with 3 loops in it. The frequency of the source is 16.5Hz. What is the fundamental frequency of the string? For the life of me I cant figure out how to solve this question. I found out that the wavelength is 4.8m but thats about it. If I use the equation fn = nf1 this is all I seem to be getting when I plug in the numbers. fn = 1 * 16.5Hz which is still equal to 16.5Hz......Id like to know what im missing here.