[填空题]
A person exerts a forcee,p/g b5zk f-ik0jg*s4 vl y4b of 55 N on the end of a door 74 cm wide. What is thq*s jn5p w0kast++ l6ke magnitude of the torque if the force is e5+ 0*sq njsalw+6p kktxerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$