[填空题]
A person exerts a force of 55 N hh0v:uqi l 8h:r(l0gnon the end o opb9q1uphgwl-k *+2kf a door 74 cm wide. What is the magnitud b+92p*- ophlkuq1 wkge 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? $m \cdot N$