[填空题]
A person exerts a force of 55 N on the end of a door 74 cm wide. f 4w)9rw(3/eiivd q afWhat is the caq0.q p,+rufwbyd2fi z+q7 5magnitude of the torque if thezd.25 p bqy+fq,0aw+qc7iuf r force is exerted (a) perpendicular to the door $m \cdot N$ (b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$