[填空题]
A person exerts a force of 55 N on the end of 4 flaz1qb.p03b8m; burz 4flgegh( t5 a door 74 cmxovaumpv ).l3025ls)t5zkar wide. What is the magnitude of l 2)ztus 3m5xv.ovr)pl5 ak0a the torque if the force is exerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$