[填空题]
A person exerts a force of 55 N on the end of a door 74 cm +c2iufg:w xp6 wide. Whkqypc dc5jm:38-uzsi204x5 g7 m wuvoat is the magnitude of the torque if theowd0 :ygxk5 m-uuqpim 5v27c3 4s czj8 force is exerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$