[填空题]
A person exerts a fomw2arqf,m hmuus vh4; n6 1g,95qp po-r /kc+ nqiy8(mrce of 55 N on the end of a door 74 cm wide. What is the magnitude of theycr(+/q n8kim 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? $m \cdot N$