Two steel guitar strings have the same length. String A has a diameter of 0.50 mm and is under 340.0 N of tension. String B has a diameter of 1.0 mm and is under a tension of 800.0 N. Find the ratio of the wave speeds, vA / vB, in these two strings. I know that the equation that I need to use is v=square root of F/u where u=the mass per length of the string. I tried doing this solving by using that equation and just plugging in the diameters. Now that I've actually sat down and thought about it, I was wondering how I could incorporate the diameters into that equation, namely how can I figure out how to the diameter is related to the mass per length ?