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Instructions.
This interactive shows the force
\(\vec{F}\) and position vector
\(\vec{r}\) for use in the moment cross product. The position vector is a vector from the moment center to any point on the line of action of the force.
You can move the tip of
\(\vec{r}\) anywhere along the line of action of
\(\vec{F}\) without changing the moment, since the moment arm
\(d_\perp = |\vec{r}| \sin \theta\) remains unchanged as you do.
