Question

One-fourth length of a spring of force constant $k$ is cut-away. The force constant of the remaining spring will be :

• A. $\frac{3}{4}k$
• B. $\frac{4}{3}k$
• C. $k$
• D. $4k$

Answer 1

Answer: (B)

$\frac{4}{3}k$

$k\propto \frac{1}{l}$

Since, one-fourth length is cut-away.

So remaining length is $\frac{3}{4}$th, hence $k$ become $\frac{4}{3}$ times ie, $k^{{}^{\prime }}=\frac{4}{3}k$.