Q. The potential energy of a certain spring when stretched through a distance s is 10 J .The amount of work done (in joule)that must be done on this spring to stretch it through an additional distance s, will be
A) 20
B) 10
C) 30
D) 40
Explanation
(d) Work done for a distance s is given by
$W = \frac{1}{2}ks^{2}$
$or\ \ 10 = \frac{1}{2}ks^{2}\ \ \ \ \ldots\ldots\ldots.(i)$
Where k is spring constant.
Now, work done for a distance 2 s is given by
$W = \frac{1}{2}K(2s)^{2} = 4 \times \frac{1}{2}ks^{2}$
$4 \times 10 = 40J$
∴Required work done
=40-10=30 J
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.