Question

In the given figure, the block displaces down to the equilibrium position by an amount (K, 2K and 3K represents stiffness of the respective springs)

• A. $\frac{9}{4}\frac{mg}{K}$
• B. $\frac{3}{7}\frac{mg}{K}$
• C. $\frac{5}{8}\frac{mg}{K}$
• D. $\frac{4}{11}\frac{mg}{K}$

Answer 1

The correct option is D $\frac{4}{11}\frac{mg}{K}$

Equivalent-stiffness $K_{eq}=\frac{3K\times K}{3K+K}+2K=\frac{11}{4}KEquatingtheweightandspringforcemg=K_{eq}xx=\frac{mg}{K_{eq}}=\frac{mg}{\frac{11}{4}K}=\frac{4}{11}\frac{mg}{K}$