[填空题]
A person exerts a force of 55 N on the end of a door 74 cm wide. Wha ncv+93+v4ujm 0;9vndjt s ith7p5g 14hyrzyot isk5syjr86 cba .5hqd5 b the magnitude of the torque if the fs k85r.5daq56 bbcyj horce is exerted
(a) perpendicular to the door $m \cdot N$
(b) at a 45 $^{\circ} $ angle to the face of the door? $m \cdot N$