[填空题]
A helicopter rotor blade can be considea -c f*y3- 8wo+h o4rw+jlukpored a long thin ro cquwrj xr69*p-hf2 n1d, as shown in Fig. 8–46.
fn9u1 -hrqx*jwr2cp6 (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? $m \cdot N$
