question_answer

For following arrangement, the value of equivalent force constant is                     

A)  \[\frac{3}{2}k\]

B)  \[\frac{2}{3}k\]

C)  \[2k\]

D)  \[3k\]

Correct Answer: B

Solution :

 Springs (2) and (3) are in parallel.   Therefore,   its equivalent force constant will be 2k. Again 2k and spring (1) are in series. Therefore, equivalent force constant \[\frac{1}{K'}=\frac{1}{k}+\frac{1}{2k}=\frac{3}{2k}\] \[K'=\frac{2}{3}k\]