[填空题]
A person exerts a force of 55 N on0+yfos w5r y 49i zx12as0h/y1qz 5qizvl/avc the end of 9kpzgo t e (0m5e998f)vjx0uqil5o a ja door 74 cm wide. What is the magnituo9xgpue 9)fj5a0 j5m(ki08 e t9qvlz ode of 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? $m \cdot N$