Final answer:
Wind-driven fires can exist with winds as low as 30 mph. The power of wind scales as the cube of wind velocity, which is an important factor in the design and potential power output of wind turbines.
Step-by-step explanation:
Wind-driven fires can begin and be influenced by relatively low wind speeds. The critical speed at which wind can significantly contribute to the spread of a fire is actually lower than what one might intuitively expect. For instance, even wind speeds as low as 30 mph (option b) can be sufficient for creating wind-driven fires. These fires can be exacerbated by higher wind speeds which provide more oxygen to the fire and can carry embers to new locations, igniting spot fires ahead of the main fire front. Understanding the impact of wind on fire behavior is crucial for firefighting and evacuation strategies.
When it comes to wind impact and power generation, it's critical to mention that the power of wind scales with the cube of wind velocity. This means that when wind speeds double, the potential power of the wind increases by a factor of eight. This is why a hurricane-strength wind of 50 m/s is significantly more powerful than a light breeze of 5 m/s. Similarly, this principle underlies the design considerations for wind turbines, where the rotor diameter and efficiency play significant roles in the power output at various wind speeds.