A spring with force constant k is initially stretched by \(x_{1}\) . If it is further stretched by \(x_{2}\) , then the increase in its potential energy is
Choose Your Option
A. \(\frac{1}{2}k(x_{2} - x_{1})^{2}\)
B. \(\frac{1}{2}k x_{2}(x_{2} + 2x_{1})\)
C. \(\frac{1}{2}k x_{1}^{2} - \frac{1}{2}k x_{2}^{2}\)
D. \(\frac{1}{2}k(x_{1} + x_{2})^{2}\)