[填空题]
A person exerts a force of 55 N on the(l naasvrh;q;r o 8dd(a,5/w.t )pdyw/d+e 6no wf,ktend of a door 74 cm wide. What is the magnitude okfe wdt6+n/ ,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? $m \cdot N$