As we know that centripetal force is given as
[tex]F = m\omega^2 R[/tex]
here we know that
m = 12000 kg
R = 18 m
here we assumed that radius is half of the length of blade as here the center of mass is concentrated at mid point of blade
[tex]\omega = 2\pi f[/tex]
[tex]\omega = 2\pi \frac{24}{60} = 0.8\pi[/tex]
now the force is given as
[tex]F = 12000\times (0.8\pi)^2 \times 18[/tex]
[tex]F = 1.36 \times 10^6 N[/tex]
so above is the centripetal force on the blade
