Q. The springs shown are identical. When $A = 4kg,$ the elongation of spring is $1\ cm.$ If $B = 6kg,$ the elongation produced by it is
A) $4\ cm$
B) $3\ cm$
C) $2\ cm$
D) $1\ cm$
Explanation
(b) $F = kx \Rightarrow mg = kx \Rightarrow m \propto kx$
$Hence\frac{m_{1}}{m_{2}} = \frac{k_{1}}{k_{2}} \times \frac{x_{1}}{x_{2}} \Rightarrow \frac{4}{6} = \frac{k}{k/2} \times \frac{1}{x_{2}}$
$\Rightarrow x_{2} = 3\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.