Answer
$0.136J$
Work Step by Step
The lost energy can be found as:
$\Delta E=E_o-E_f$
The formula can be rewritten as:
$E_o-E_f=\frac{1}{2}kA_o^2-\frac{1}{2}kA_f^2=\frac{1}{2}k(A_o^2-A_f^2)$
Substituting the values in this formula to find the lost energy;
$\frac{1}{2}k(A_o^2-A_f^2)=\frac{1}{2}(10.0N/m)((.250m)^2-(.188m)^2)=0.136J$
