[填空题]
A person exerts a force of 55i kr,vnpu6/1 g N on f,r;bmyq:mq* the end of a door 74 cm wide. What is the magnitude *;m,rbmqq: fy of 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? $m \cdot N$