The work done by the unstretched spring is 5 J.
Hooke's law states that the extension of a given material is directly proportional to the force applied as log as the elastic limit is not exceeded. Thus we have to know that; F = Ke
F = force applied
K = force constant
e = extension
Using the graph;
K = F/e
F = 200N
e = 5 cm or 5 * 10^-2 m
K = 200N/ 5 * 10^-2 m
K = 4000 N/m
Now;
Work = 1/2Ke^2
Work = 0.5 * 4000 N/m * (5 * 10^-2 m)^2
Work = 5 J
Learn more about Hooke's law:https://brainly.com/question/13348278
#SPJ1