An aircraft is travelling north at $60\,\text{m s}^{-1}$, and then a cross-wind begins to blow from the east. The wind speed is $13\,\text{m s}^{-1}$. What is the magnitude of the aircraft’s velocity when the wind is blowing?
- A47 m/s
- B59 m/s
- C61 m/s
- D73 m/s