The gravitational force acting on the mass is,
[tex]F=mg[/tex]
The spring constant of the spring can be given as,
[tex]k=\frac{F}{d}[/tex]
Substitute the known expression,
[tex]k=\frac{mg}{d}[/tex]
Substitute the known values,
[tex]\begin{gathered} k=\frac{(0.368kg)(9.8m/s^2)}{(12.3\text{ cm)(}\frac{1\text{ m}}{100\text{ cm}})}(\frac{1\text{ N}}{1kgm/s^2}) \\ \approx29.3\text{ N/m} \end{gathered}[/tex]
The work done to stretch the spring is,
[tex]W=\frac{1}{2}k(2x)^2[/tex]
Here, x is the amount of spring stretched in part (b).
Substitute the known values,
[tex]\begin{gathered} W=\frac{1}{2}(29.3N/m)(2(0.165m))^2(\frac{1\text{ J}}{1\text{ Nm}}) \\ \approx1.60\text{ J} \end{gathered}[/tex]
Thus, the work done to stretch the spring is 1.60 J.