The potential energy stored in a spring is given by:
[tex]U=\frac{1}{2}kx^2[/tex]where k is the spring constant and x is the distance the spring is compressed or elongated from the equilibrium position. In this case we have that:
[tex]\begin{gathered} k=765 \\ x=0.375 \end{gathered}[/tex]Plugging these in the expression for the potential energy we have:
[tex]\begin{gathered} U=\frac{1}{2}(765)(0.375) \\ U=53.8 \end{gathered}[/tex]Therefore, the energy stored in the spring is 53.8 J
