Answer:
338N
Explanation:
Use the formula [tex]f=\frac{\sqrt{\frac{T}{\frac{M}{L}} } }{2L}[/tex]
f is the frequency, T the string tension, M the mass, and L the length
convert units to seconds, kilograms, meters
[tex]65Hz\ =\ \frac{\sqrt{\frac{T}{\frac{0.005kg}{m}}}}{2\cdot2m}[/tex]
now solve for T
sqrt(T/.005) = 65*4 = 260
T = 338N