[填空题]
A helicopter rotor blade can be considered a8 io:v)mv,pio7z y q4e long thin9w(3t6 dz pn4w92 cf1zmz kndi rod, as shown in Fig. 8–46 wzt94c(z63m91wiz2 nk f pndd. (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? $m \cdot N$