• # question_answer The potential energy of a certain spring when stretched through a distance S is 10 joule. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance S will be A)  30                 B)  40C)  10                 D)  20

As given in the problem,$\frac{1}{2}k{{s}^{2}}=10\,J$ $\therefore$$\frac{1}{2}k\left[ {{(25)}^{2}}-{{(s)}^{2}} \right]=3\times \frac{1}{2}k{{s}^{2}}=3\times 10=30\,J.$ Hence, the correction option is [a].