Let initial length be $I_1$
Final length $I_2=I_1 \times \frac{144}{100}$
$T_1=2 \pi \sqrt{\frac{l_1}{g}}$
$T_2=2 \pi \sqrt{\frac{I_1}{g} \times \frac{144}{100}}$
or $T_2=1.2 T_1$
$T_1=60\,s$
So $T_2=72 \,s$
(Round off to the Nearest Integer)
$(A)$ Restoring force is directly proportional to the displacement.
$(B)$ The acceleration and displacement are opposite in direction.
$(C)$ The velocity is maximum at mean position.
$(D)$ The acceleration is minimum at extreme points.
Choose the correct answer from the options given below :
