Answer:
[tex]\huge\boxed{\sf f=3.225 \ Hz}[/tex]
Explanation:
Length = L = 2 m
Speed = v = 12.9 m/s
Fundamental frequency = f = ?
[tex]\displaystyle f =\frac{v}{2L}[/tex]
Put the given data in the above formula.
[tex]\displaystyle f = \frac{12.9}{2(2)} \\\\f=\frac{12.9}{4} \\\\f=3.225 \ Hz\\\\\rule[225]{225}{2}[/tex]