An object starts from rest and accelerates uniformly until its speed reaches $v$. It then continues at the constant speed $v$ for $8.0\,\text{s}$ before it decelerates uniformly to rest. The overall time taken is $12.0\,\text{s}$, and the total distance covered is $60\,\text{m}$. Calculate the speed $v$.
- A$3.0\,\text{m s}^{-1}$
- B$5.0\,\text{m s}^{-1}$
- C$6.0\,\text{m s}^{-1}$
- D$15\,\text{m s}^{-1}$