[填空题]
A helicopter rotor blade can be considered a long thin t 0l1 ygpd1bp3rod,hvlfp,iok q x.n204a6 ii 00kz as shown in Fig. 8–46. o0liz4fhikp6x0.a k, n iq0v2 (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? $m \cdot N$