[填空题]
A person exerts a force of 55 N on ms10ta,5g jiv the enw o*eb) h/i*5xl x9bekd of a door 74 cm wide. What is the magnitude of the torque if the force is exerte ik)9ebx5h/oxb *lwe* d (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$