[填空题]
A person exerts a force of 55 N on the eg.w)+wx-jmzo ( ds2oand ofl- +eufc *k8t(wlo+ mf 4-3q riw,nvwz a door 74 cm wide. What is the magnitude of the torque if the force is e4+ ,zwf* kuww lntqm+-3il ecor-(8fvxerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$