[填空题]
A helicopter rotor blade cam9.yj*lpb gqu :a/v/ mn be conscig;ln )q* v 3nctp13sidered a long thin rod, as shown in Fig. 8–46 cnt qi 1*)ns3cv;3pgl. (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? $m \cdot N$