[填空题]
A helicopter rotor blaeep,nhv q3*5l (sgt: fde can be coe+lfe/npm j4n 8z8c2dnsidered a long thin rod, as shown in Fig. 8–46.nmpef2j nl/8 ce4z8+d (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? $m \cdot N$