[填空题]
A person exerts a force of5m)e;yka8b 3:l x2 lxzijzu w+8p/zlh 55 N on the endk6k2mx:* 8qtny mb3o16*gbewt- pi qq of a door 74 cm wide. What is the magnitude of3 ik2b yoxw g8tqe q-ptb:6*6mn*k1mq 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? $m \cdot N$