In this display use the mouse button to mark the position of a particle and drag the mouse to draw a linear momentum vector from the particle's position. Then click on the Action button repeatedly for a snapshot of the angular momentum situation at 1 second intervals. Notice that in the Straight Line Angular Momentum display, there is indeed an angular momentum when the particle moves in a straight line at constant velocity. It is given by the *L*=*r*X*p* relationship. Also notice that the angular momentum remains constant throughout the run. The magnitude of the angular momentum is |r| times |p| times the sine of the angle between them. As the particle moves, the magnitude of the position vector, |r|, changes just enough to compensate for the change in the sine of the angle between the position vector and the constant linear momentum.