Question

What is the equivalent spring constant for the syatem shown below in the figure?

• A. $\frac{5k}{6}$
• B. $\frac{6k}{5}$
• C. $\frac{2k}{3}$
• D. $\frac{3k}{2}$

Answer 1

The correct option is B $\frac{6k}{5}$

Given system is as shown below


From the arrangement we can see that, $A$, $B$ and $C$ are in parallel together, also $D$ and $E$ are together in parallel.
So, we have
$K_{ABC}=k+k+k=3k$
also, $K_{DE}=k+k=2k$
Now, these two equavalents are in series, so the final eqivalent spring constant is given as
$K_{eq}=\frac{3k\times 2k}{3k+2k}=\frac{6k}{5}$