posted by Lorax .
trap door of length and width 1.65 m is held open at an angle of 65.0 degree with respect to the floor. A rope is attached to the raised edge of the door and fastened to the wall behind the door in such a position that the rope pulls perpendicularly to the trap door. If the mass of the trap door is 16.8 kg, what is the torque exerted on the trap door by the rope?
The torque applied by the rope must equal the torque applied by the weight. Compute it at the hinge, to make the problem simpler. The center of mass of the door, where the weight acts, is in the middle of the door.
Torque = M*g*(width/2)*cos65
= 57.4 N-m