A $0.15\,\text{kg}$ mass hangs from a vertical spring. The mass is pulled downward until the spring has lengthened by $12\,\text{cm}$ from its natural length. The spring constant of the spring is $30\,\text{N m}^{-1}$. Determine the magnitude of the spring's initial acceleration at the instant it is released?
- A$14\,\text{m s}^{-2}$
- B$24\,\text{m s}^{-2}$
- C$28\,\text{m s}^{-2}$
- D$34\,\text{m s}^{-2}$