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Question
Two forces each of magnitude 10 N act vertically upwards and downwards respectively at the two ends A and B of a uniform rod of length 4 m which is pivoted at its midpoint O as shown in the figure. Determine the magnitude of the resultant moment of forces about the pivot O.

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Solution
F = 10 N on each side
distance of each force from O = 2m
Both are clockwise moments
i.e. 10 N × 2m + 10 N × 2m
= 20 N m + 20 N m
= 40 N m
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