Mechanics, specifically Moment question

In summary, the conversation discusses finding the moment at a specific point (D) for a couple. The equation for calculating moment for couples is given, and there is a question about whether the resultant force and moment would be the same everywhere. A hint is given to consider the line of action when determining the moment.
  • #1
SirMarksAlot
19
0

Homework Statement


scan0001.jpg


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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  • #2
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 ?
 
  • #3
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?
 

FAQ: Mechanics, specifically Moment question

1. What is a moment in mechanics?

A moment in mechanics refers to the turning effect produced by a force around a pivot point. It is a measure of the tendency of a force to cause an object to rotate.

2. How is moment calculated?

The moment of a force is calculated by multiplying the magnitude of the force by the perpendicular distance from the pivot point to the line of action of the force. The unit of moment is newton-meter (Nm) in the SI system.

3. What is the difference between a positive and a negative moment?

A positive moment indicates a counterclockwise rotation, while a negative moment indicates a clockwise rotation. This depends on the direction of the force and the chosen pivot point.

4. How does the distance affect the moment of a force?

The greater the distance between the force and the pivot point, the greater the moment of the force. This means that a force applied farther away from the pivot point will have a greater turning effect than the same force applied closer to the pivot point.

5. What is the principle of moments?

The principle of moments states that for a body to be in equilibrium, the sum of clockwise moments must be equal to the sum of counterclockwise moments. This means that the total moment acting on an object must be zero for it to be in rotational equilibrium.

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