Torque of a man doing exercises against a wall?

AI Thread Summary
The discussion focuses on calculating the net torque on a person weighing 800 N, with applied forces of 100 N and 900 N, about axes through points A, B, and C. Participants express confusion about determining the axis of rotation and the lever arm in the torque calculations. Despite the uncertainties, the final calculated torques are 207 Nm, 145 Nm, and 95.7 Nm, all in a clockwise direction. The angles in the provided figure are confirmed to be correct, while the specific force values are to be disregarded. The thread highlights the challenges of understanding torque mechanics in this context.
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Homework Statement



The person in figure 8.31 weighs 800 N. the forces F1 and F2 have magnitudes of 100 N and 900 N respective. Assume the force of gravity acts downward through point A as shown. Determine the net torque on the person about axes through points A, B, and C perpendicular to the plane of the paper.

Please neglect the force values given in this picture
The angles are correct, however.
Picture: http://img153.imageshack.us/img153/3927/picture4cb.png

Homework Equations



. . . .

The Attempt at a Solution



I don't know where to start!
I don't know where to place the axis of rotation. And what about the lever arm?
I really don't know how to align my axis.
 
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Here are the answers:
207 Nm clockwise
145 Nm clockwise
95.7 Nm clockwise
 

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