Find Moment and Force in 3-D Plane

[megr_ftw]

I really don't need an answer to a question but I'm trying to show there are two ways to find the moment about an axis in a 3-d plane when a force is being applied.
I know you draw the "r" vector from the axis to the point of where the force is being applied, but sometimes there are two different ways to draw the r vector. My question is that the moments should be equal regardless where the r vector is?

 

[nvn]

megr_ftw: What do you mean by "two ways"? Did you mean to say "many ways"? If so, and if I am interpreting your question correctly, I think the answer is yes, there are infinite ways to draw the r vector that produce equal moment. And there is a program that might address this issue in post 2195467[/color] (post 6), which you can use in Octave[/color] (free). Or you can convert it to any other language.

However, if you reverse the direction of the r vector, it reverses the sign of the moment, which is not equal but opposite.

 

[kivine]

usually the head of the force joins the tail of the vector r