[填空题]
A helicopter rotor blade cah 6n(rr;07j nv0ra xvk( 7c- nqlwc2kon be considered a long thin rod, as shown in Fig. 8–l,n8z,q5fy/9z t tzks46. nskzqtytl fz598/, z, (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? $m \cdot N$