A boy launches a stone horizontally at $10\,\text{m s}^{-1}$ from the roof of a building. The building is $8.0\,\text{m}$ high. The stone follows a curved trajectory before landing on the ground, as shown in the diagram. How long does it take the stone to reach the ground? (Air resistance can be neglected.)
- A$0.61\,\text{s}$
- B$0.80\,\text{s}$
- C$1.3\,\text{s}$
- D$1.6\,\text{s}$