# Determine the moment about a given point

• wannawin
In summary, the conversation involves finding moments about points A, B, and D using the equation Mx = F * d. The leftmost force at point A produces no moment, but there is confusion about the distances for the other two forces. The 52 kN force needs to be broken down into its vertical and horizontal components, and the golden rule for calculating moments is mentioned. There is also mention of finding the angle in a triangle and using it to find the horizontal distance. A warning is given about a potentially dangerous website.
wannawin

## Homework Statement

I'm trying to find the moments about points A,B and D respectively.

Mx= F * d

## The Attempt at a Solution

Correct me if I'm wrong, but on point A the leftmost force produces no moment. After that I'm a little confused about what to use for the distances of the other two forces.

wannawin said:

## Homework Statement

I'm trying to find the moments about points A,B and D respectively.

Mx= F * d

## The Attempt at a Solution

Correct me if I'm wrong, but on point A the leftmost force produces no moment.
That is correct.
After that I'm a little confused about what to use for the distances of the other two forces.
Breakup the 52 kN force into its vertical and horizontal vector components, applied where the arrow of the 52 kN force is is touching the line. Then remember the golden rule: The moment of a force, or component of that force, is equal to the force, or component of that force, times the perpendicular distance from the line of action of the force, or component of that force, to the point about which you are summing moments.
For example, looking now at the 93 kN force, its line of action is a vertical line. The moment of that force about A is then 93*(___?__), clockwise. Now calculate the moments for each of the force components of the 52 kN force, and add them all up.

you may also need to find the angle in the triangle made after a square.

sorry rectangle

so I can use 1.8m as the vertical distance, but by the way it looks I guess I have to find out the length of x and add it to 7 in order to find the horizontal distance.

For 52 sin 28 its 1.8 m and for 52 cos 28 you have to find the angle to find the distance which should be added with 7 m

When I click on the picture posted in post 1, it says, "This web page has been identified as dangerous. For your own safety, please close this window now, and never return to this web site." Just wanted to warn you guys. It might be dangerous.

## What does it mean to determine the moment about a given point?

Determining the moment about a given point is a physics concept that involves calculating the rotational effect of a force on an object. It takes into account the magnitude and direction of the force as well as the distance between the force and the point.

## What is the formula for determining the moment about a given point?

The formula for determining the moment about a given point is M = F x d, where M is the moment, F is the force and d is the perpendicular distance between the force and the point. This formula is often represented by the cross product symbol (x).

## How is the moment about a given point different from torque?

The moment about a given point and torque are related concepts, but they are not exactly the same. Moment is a general term that describes the rotational effect of a force, while torque specifically refers to the rotational force applied to an object.

## What are some real-life applications of determining the moment about a given point?

Determining the moment about a given point is important in many fields, including engineering, architecture, and physics. It is used to analyze the stability and strength of structures, such as buildings and bridges. It is also used in designing machines and vehicles, such as cars and airplanes.

## What are some common misconceptions about determining the moment about a given point?

One common misconception is that only forces acting in a vertical or horizontal direction can create a moment. In reality, any force that has a component that is not aligned with the point of rotation can create a moment. Another misconception is that the magnitude of the force is the only important factor in determining the moment, when in fact, the distance from the force to the point is equally important.

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