[填空题]
A person exerts a force of 55 N on t9ei ukzx20:kxng zw1uc8d 5udx ( -.dthe end of a h*6y b3diw83qyya q 7adoor 74 cm wide. What is the magnitude of the toybdq7w 36q3iyahy * 8arque 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? $m \cdot N$