[填空题]
A helicopter rotor blade h(pc/, wommo a,aek3k,g0q2 zoy /u2soou9h + u;ex4r2he3g lcan be considered a long thin rod, as shown in Fig. 8–46.hge+r u/ olu;o2h y32xu9s4oe (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? $m \cdot N$
