Thế năng khi kéo dãn được 10cm \(\begin{align} & {{\text{W}}_{t}}=\frac{1}{2}k.{{x}^{2}} \\ & \Leftrightarrow \frac{{{\text{W}}_{t1}}}{{{\text{W}}_{t2}}}=\frac{x_{1}^{2}}{x_{2}^{2}} \\ & \Rightarrow {{\text{W}}_{t1}}=\frac{x_{1}^{2}}{x_{2}^{2}}{{\text{W}}_{t2}}=\frac{0,{{1}^{2}}}{0,{{01}^{2}}}.0,1=10J \\ \end{align}\)
công \(A=\left| {{\text{W}}_{t1}}-{{\text{W}}_{t}} \right|=10J\)
