A student is positioned $180\ \text{m}$ in front of a vertical, flat cliff and strikes two pieces of wood together to create a brief, loud sound. A timer shows that the echo of the sound occurs $1.5$ seconds after the pieces of wood are struck together. Using this result, what is the speed of sound?
- A$120\ \text{m s}^{-1}$
- B$240\ \text{m s}^{-1}$
- C$270\ \text{m s}^{-1}$
- D$540\ \text{m s}^{-1}$