A mass $m$ is attached to two identical springs having spring constant $k$ as shown in the figure. The natural frequency $\omega$ of this single degree of freedom system is
- $\sqrt{\dfrac{2k}{m}} \\$
- $\sqrt{\dfrac{k}{m}} \\$
- $\sqrt{\dfrac{k}{2m}} \\ $
- $\sqrt{\dfrac{4k}{m}}$