[填空题]
A helicopter rotor blade can be considered a long thin rod, as showlu2, / egwa-rin in Fig. 8–4ui ,- gaerl2/w/ kzuo - 8d0z;8 ow-u)jtajwla6.a/k8ozoazjw j;)8u0uld- tw- (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? $m \cdot N$