Answer
$f_1=77Hz$
Work Step by Step
The frequency of the $nth$ harmonic is equal to $$f_n=\frac{nv}{2L}$$ Since the tone is the fundamental frequency, the frequency is $$f_1=\frac{v}{2L}$$ The formula for the speed of a wave on a string is equal to $$v=\sqrt{\frac{F_T}{\mu}}$$ Find the length density $\mu$ using the formula $$\mu=\frac{M}{L}=\frac{2.6g}{1.5m}=1.7g/m=0.0017kg/m$$ Substituting known values of $F_T=93N$ and $\mu=0.0017kg/m$ yields a velocity of $$v=\sqrt{\frac{93N}{0.0017kg/m}}=230m/s$$ Substituting known values of $v=230m/s$ and $L=1.5m$ into the frequency equation yields a frequency of $$f_1=\frac{230m/s}{2(1.5m)}=77Hz$$
