[填空题]
A person exerts a fod+axncnr5l*e s) 7p u7w ( qfj1mcydn ;b7e1kyov x28.rce of 55 N on the end of a door 74 cm wide. What is the magnitude of the torque if the foy7.b w ncfed1q8ykjv1mx(;o 2rce is exerted
(a) perpendicular to the door $m \cdot N$
(b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$