Moment, Torque—Forces Acting at a Distance

Determine the sum of the moment of the forces about point O shown in F ure 10.23. 

Note that in calculating the moment of each force, the perpendicular distance between the line of action of each force and the point 0 is used. Moreover, for book keepit sake, we assigned a positive sign to counterclockwise rotation. 

Reforring to Example 10.15, note that two forces that ate equal in magnitude and opposite in direcdon (not having the same line of acdon) consdmte a an le. As you can see om the results of this example, the moment created by a couple is equal to the magnitude of dther force times the perpendicular distance between the line of acdon of the forces involved. Also note for this problem, we ass ed a posidve sign to clockwise rotadon. Since the sum of the moments has a posidve value, the overall tendency of forces is to turn the object clockwise. 

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