Mechanics, specifically Moment question

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The discussion revolves around understanding moments in mechanics, specifically regarding the line of action and its implications for calculating moments at a point. The participant is uncertain about the question's requirements and whether the resultant force remains constant when considering moments at different locations. It is noted that for a couple, the moment is indeed the same regardless of the point of application, but the force's location affects the moment calculation. Clarification is sought on the concept of the line of action, which is described as the direction along which the force acts. Understanding these principles is crucial for solving the problem accurately.
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Homework Statement


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Also, I am not entirely sure what the question is exactly asking. Also, what does the line of action represent?

Homework Equations



M = Fx(Perpendicular distance) + Fy(Perpendicular distance)

For couples:

M=Fd

The Attempt at a Solution



i was thinking that i need to find the moment at D, but wouldn't the resultant force still be the same? except located at D? However, since this is a couple, would the moment be the same everywhere?
 
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A force located at D doesn't give a moment (in D).
You shoud find a force located somewhere else than D.

A hint: the text speaks about LINE of action. Why ?
 
Wouldnt the force anywhere still be 48 N since the couple cancels each other out, and leaves only the moment?

Also, is the line of action just the direction/line that the force follows?
 
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