Applet shows the angular momentum vector about a point on the axis of a circle of a particle (m) ,moving round a circular path of radius R at v.
The green vector is the linear momentum vector(p), the blue vector is the position vector (r) and the black vector is the angular momentum vector(L).
The relation between the vectors is L = r ´ p
The red and magenta vectors are the radial and axial components of the angular momentum vector and have magnitudes of mvR and mvh respectively.
Notice that during the rotation of the particle the axial component of angular momentum remains unchanged and the radial component rotates at the same angular speed as the particle itself.
Experiment by changing the height of the reference point above the plane of the circle, the radius of the circle and the angular velocity of the particle.
Double clicking anywhere in the applet area at any point shifts the origin to that point. Dragging with the mouse changes the orientation of the axes.
The checkbox at the bottom right corner, if checked, causes a half plane containing the z- axis to be displayed.