Answer:
[tex]2.0\:\mathrm{J}[/tex]
Explanation:
The elastic potential energy of a spring is given by:
[tex]U_s=\frac{1}{2}kx^2[/tex], where [tex]k[/tex] is the spring constant and [tex]x[/tex] is the displacement from equilibrium.
Solving for [tex]U_s[/tex], we get:
[tex]U_s=\frac{1}{2}\cdot 100\cdot 0.2^2,\\U_s=\boxed{2.0\:\mathrm{J}}[/tex]