Given,
The mass attached to the spring, m=0.520 kg
The stretching of the spring, x=18.7 cm=0.187 m
The restoring force of spring is given by,
[tex]F=kx[/tex]Where k is the spring constant of the spring.
The force F is equal to the weight of the mass attached.
Thus,
[tex]\begin{gathered} F=mg=kx \\ \Rightarrow k=\frac{mg}{x} \end{gathered}[/tex]Where g is the acceleration due to gravity.
On substituting the known values,
[tex]\begin{gathered} k=\frac{0.520\times9.8}{0.187} \\ =27.3\text{ N/m} \end{gathered}[/tex]The frequency of the spring is given by,
[tex]f=\frac{1}{T}=\frac{1}{2\pi}\sqrt[]{\frac{k}{m}}[/tex]where T is the period of oscillation of spring.
On substituting the known values,
[tex]\begin{gathered} f=\frac{1}{2\pi}\sqrt[]{\frac{27.3}{0.520}} \\ =1.15\text{ Hz} \end{gathered}[/tex]Thus the frequency of oscillation of the spring is 1.15 Hz.