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Example - Force –System Resultants -- Moments

The bent ABCDEG in the figure below is subjected to forces of 700 N, 300 N, and

500 N in the directions shown at locations G, C, and B respectively. Determine the

resultant force, F_r, passing through point A and the resultant moment, M_rA. All

dimensions are in meters.

Strategy:

Step 1	Express each force as a vector. One way is to determine the starting and end points for each force vector.
Step 2	Add the three force vectors to obtain the resultant force.
Step 3	Determine the position vectors from A to any convenient point on the line of action for each force vector.
Step 4	Calculate the moment of each force vector about point A by using the vector product (r x F).
Step 5	Sum each of the three moments obtained in Step 4 to obtain the resultant moment about point A.