[填空题]
A person exerts a for6powdyil r9 k49* z,p1/knxn tm(shn7ce of 55 pc3i(c ie9jd*c* vvv0N on the end of a door 74 cm wide. What is the magnitude **vvc d (v0c3ij9eicpof 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? $m \cdot N$