EXAMPLE 5.0.8: MOMENT OF SPATIAL FORCES

Brackets A and B along with wire CD support a rectangular plate. Determine the moment about A of the force exerted by the wire on point C if the tension in the wire is 200N.

In this example the reference point is away from the origin.

The moment about A of the Force at Cd can be computed as

                            

                            

For position vector at C (with respect to A):      

For position vector at D (with respect to A):      


The Cartesian vector form of force on CD is






For the moment, take the cross product of the vectors.

Using point C:  

              

             

           

                                                        ANSWER


Using point D:

            

            

            

                                                      ANSWER


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