Hi there!
Recall the equation for work done by a spring:
[tex]\large\boxed{W = \frac{1}{2}k \Delta x^2}}[/tex]
Δx = change in distance from equilibrium (m)
k = Spring constant (N/m)
W = Work (J)
Rearrange the equation to solve for 'k'.
We get a working equation:
[tex]\large\boxed{k = \frac{2W}{\Delta x^2}}[/tex]
Plug in the given values:
[tex]k = \frac{2(87)}{(2.9-1.4)^2} = \boxed{77.33 N/m}}[/tex]
