Calculating Moment about a Point: Understanding FDCsin and FDCcos

In summary, the concept of "moment" in physics refers to the turning effect of a force around a specific point or axis. FDCsin and FDCcos are components of the force that are crucial in calculating the moment about a point, with FDCsin representing the perpendicular distance and FDCcos representing the parallel distance. Clockwise and counterclockwise moments differ in the direction of rotation they cause. The moment of a force can be calculated by multiplying the magnitude of the force by FDCsin, with the direction determined by the right-hand rule. Understanding FDCsin and FDCcos is significant in accurately calculating the moment and analyzing the stability and equilibrium of an object.
  • #1
chetzread
801
1
1. The problem sttatement, all variables and given/known data
i don't understand the moment FDC(sin18.43)(9) , I think it's wrong..
http://imgur.com/a/qPdqf

Homework Equations

The Attempt at a Solution


I think it should be FDC(cos18.43)(3), am i right?
the r is the perpedicular distance from D to force FDC, i have circled it...
Or I'm wrong? FDCsin18.43)(9) represent other moment?
 
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  • #2
sorry, photo here
 

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  • #3
there' also moment caused by other forces such as 2KN at B , why didnt the author consider that? the 2kN force can cause moment about I ,right?
 
  • #4
is the author wrong ?
 

1. What is the concept of "moment" in physics?

The concept of "moment" in physics refers to the turning effect of a force around a specific point or axis. It is a measure of the tendency of a force to cause an object to rotate.

2. How do FDCsin and FDCcos relate to calculating moment about a point?

FDCsin and FDCcos are components of the force acting on an object, with FDCsin representing the perpendicular distance from the point to the line of action of the force, and FDCcos representing the parallel distance. These components are essential in calculating the moment of a force about a point, as they determine the magnitude and direction of the turning effect of the force.

3. What is the difference between clockwise and counterclockwise moment?

Clockwise moment is the turning effect of a force that causes an object to rotate in a clockwise direction around a point or axis. Counterclockwise moment, on the other hand, is the turning effect of a force that causes an object to rotate in a counterclockwise direction. The direction of the moment depends on the direction of the force and the direction of rotation it causes.

4. How do you calculate the moment of a force about a point?

The moment of a force about a point can be calculated by multiplying the magnitude of the force by the perpendicular distance from the point to the line of action of the force (FDCsin). The direction of the moment is determined by the right-hand rule, with the thumb pointing in the direction of the force and the fingers pointing in the direction of rotation.

5. What is the significance of understanding FDCsin and FDCcos in calculating moment?

Understanding FDCsin and FDCcos is crucial in accurately calculating the moment of a force about a point. These components help determine the magnitude and direction of the moment, which is essential in analyzing the stability and equilibrium of an object. Without a thorough understanding of these components, the moment of a force cannot be accurately calculated.

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