A spring balance is made from a spring that has an initial length of $20.0\,\text{cm}$ and a hook fixed to it. When a fish with mass $3.0\,\text{kg}$ is hung from the hook, the spring’s length increases to $27.0\,\text{cm}$. What is the spring constant of the spring?
- A$4.2\,\text{N m}^{-1}$
- B$43\,\text{N m}^{-1}$
- C$110\,\text{N m}^{-1}$
- D$420\,\text{N m}^{-1}$