[填空题]
A helicopter rotor bl mivjqf+.z k66 hi7.xlade can be considered a :l6aulmfe68 bgbu( w*bwd l35vdwj). long thin rod, as shown in Fig. 8–46.5ewmu8af* ub .3jl6 bl6: lwdgbd)v(w (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? $m \cdot N$