[填空题]
A helicopter rotor blade canwo 91gcohbgo9/+w*j3 g y x5nj be consitf;- r 2tiz 5ps8wy3lwdered a long thin rod, as shown in Fig. 8–4f;i5y83r 2t wlt pz-sw6. (a) If each of the three rotor helicopter blades is 3.75 m long and has a mass of 160 kg, calculate the moment of inertia of the three rotor blades about the axis of rotation. $kg \cdot m^2$ (b) How much torque must the motor apply to bring the blades up to a speed of 5 $rev/s$ in 8.0 s? $m \cdot N$