[填空题]
A person exerts a for h6d)qw52 *9e u9ydxelvv kx6gkogg ;mdeo bifg/c-tj2+ .d1 6ce of 55 N on the end of a door 74 cm wide. What is the magnitude of the torque if the gim od; ge+kog.1fj/bcd-2t 6force is exerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$