Given,
The mass, m=35 kg
The displacement of the spring from its equilibrium position, x=65 cm=0.65 m
The magnitude of the restoring force of the spring is given by,
[tex]F=kx[/tex]And the restoring force will be equal to the weight due to the mass attached to the spring.
Therefore,
[tex]F=mg=kx[/tex]Where g is the acceleration due to gravity.
On rearranging the above equation,
[tex]k=\frac{mg}{x}[/tex]On substituting the known values,
[tex]\begin{gathered} k=\frac{35\times9.8}{0.65} \\ =527.7\text{ N/m} \end{gathered}[/tex]Thus the value of the spring constant of the given spring is 527.7 N/m