[填空题]
A person exerts a forc z0r -4v .k6uz*2. oebk 0opnymwa.yjze of 55 N onw5enj. 9z7z4/ *djc zamkuxjcf. ;0ug the end of a door 74 cm wide. What is the magnitude of.kuwz7c f0d. c n549gz/;jj*a jzuem x 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? $m \cdot N$