Given:
Centripetal acceleration = 105.8 m/s²
velocity = 23 m/s
The formula of centripetal acceleration is:
Ac = v² / r
where v is the velocity and r is the radius of the circle formed. The radius is the length of the helicopter blade.
105.8 m/s² = (23m/s)² / r
r = (23m/s)² / 105.8 m/s²
r = 529 m²/s² * s²/105.8 m
r = 5 m
The helicopter blade is 5 meters long.