[填空题]
A helicopter rotor bl0 g 8z)dqsm/isqsd66 jade can be considered a long thin rod, as shown inok3 feit1gyf 3( )f qyeb,.sz( Fig. 8–4b(.sf 1k e(,)gzeyifyf3qt o36. (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? $m \cdot N$