The force <math> \vec F = -k \vec x</math> can be interpreted as a vector field depending on the displacement vector <math>\vec x</math>. Since this field is the gradient of the function <math>\frac{1}{2} k|x|^2</math>, this means that <math>\vec F</math> is a [[conservative field]]. As a result, <math>E = \frac{1}{2} kx^2</math> is conserved, and is the potential energy stored in the string. Moreover, <math>E</math> depends only on <math>\vec x</math>, and not the path that the particle takes to get to <math>\vec x</math>, and so it is said to be a [[path independent]] quantity. | The force <math> \vec F = -k \vec x</math> can be interpreted as a vector field depending on the displacement vector <math>\vec x</math>. Since this field is the gradient of the function <math>\frac{1}{2} k|x|^2</math>, this means that <math>\vec F</math> is a [[conservative field]]. As a result, <math>E = \frac{1}{2} kx^2</math> is conserved, and is the potential energy stored in the string. Moreover, <math>E</math> depends only on <math>\vec x</math>, and not the path that the particle takes to get to <math>\vec x</math>, and so it is said to be a [[path independent]] quantity. |