Which statement best describes the wind speed measurement limit mentioned in the material?

Which statement best describes the wind speed measurement limit mentioned in the material?

• A. Cup anemometers can measure down to 0.1 m/s
• B. Cup anemometers can measure down to 0.5 m/s
• C. Cup anemometers can measure down to 1.0 m/s
• D. Cup anemometers cannot measure wind speeds below 2 m/s

Answer: (B)

Cup anemometers measure wind by rotating cups, and they only provide reliable readings once the wind can overcome static friction and the drag of the mechanism. This starting threshold is typically around 0.5 m/s, so measurements become dependable starting near that speed. Below this, the rotor may either not spin consistently or produce readings dominated by noise, making the data unreliable. Therefore, 0.5 m/s best describes the measurement limit. The other options aren’t representative: 0.1 m/s is too low for typical cup designs, 1.0 m/s is above the limit rather than describing where reliability begins, and claiming they cannot measure below 2 m/s overstates the limitation.

Cup anemometers measure wind by rotating cups, and they only provide reliable readings once the wind can overcome static friction and the drag of the mechanism. This starting threshold is typically around 0.5 m/s, so measurements become dependable starting near that speed. Below this, the rotor may either not spin consistently or produce readings dominated by noise, making the data unreliable. Therefore, 0.5 m/s best describes the measurement limit. The other options aren’t representative: 0.1 m/s is too low for typical cup designs, 1.0 m/s is above the limit rather than describing where reliability begins, and claiming they cannot measure below 2 m/s overstates the limitation.