[填空题]
A person exerts a forcehml )t5(gyth r7fc ;w65tzk 6l of 5 bk3yy9f1w4*ywx3lv k 5 N on the end of a door 74 cm wide. What is the magnitude of the torque if the force is e31*wkvkyl fybw4xy 93xerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$