Moment 3D


This shows a position vector , , and a force vector, and the moment created by the force located at the position about the origin. In this case the moment is a vector, . The moment is also called a torque. The position can be modified by moving the blue dot and the force can be changed by moving the red dot. The force is shown bolder located at the position vector tip.


  • Rotate the view and see if you can tell how the vectors are oriented.
If view the r and F vectors aligned what angle does the moment vector make with the other two vectors. How does the moment vary when you move the points.
  • Check Angle
This will show the angle between the position and force vectors. How does the moment magnitude vary with the angle? What happens as the angle approaches 0 by positioning the blue and red dots over each other?
  • Check Components
  • Check Mz
This will show the position vector components and some of the force vector components. You can then slide the force components to the coordinate planes by moving slide_F. We a concerned about the moment about the z axis so we can move the position vector components along the z axis with the slider slide_r. View this result from the z axis. How does this compare to the two-dimensional moment calculation by components?
  • Check Mx or My
This will show the components for calculating the moment about the given axis. Looking down the appropriate axis and comment on how it compares to the z axis above? It may be helpful to keep all components positive to see where the formulas come from.
  • Check Parallelogram
This will show the parallelogram made from the two vectors. View this down each axis. How does the area viewed down the axis compare with the components of the Moment?

Video of the Applet