Q. 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) 40
C) 10
D) 20
Explanation
(a) $\frac{1}{2}kS^{2} = 10\ J$ [Given in the problem]
$\frac{1}{2}k\left\lbrack (2S)^{2} - (S)^{2} \right\rbrack = 3 \times \frac{1}{2}kS^{2} = 3 \times 10 = 30\ J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.