Q7.7 Two particles, each of mass and speed , travel in opposite directions along parallel
lines separated by a distance . Show that the angular momentum vector of the two
particle system is the same whatever be the point about which the angular momentum is taken.
Assume two points (say A, B) separated by distance d.
So the angular momentum of a point about point A is given by :
And about point B :
Now assume a point between A and B as C which is at y distance from point B.
Now the angular momentum becomes :
Thus it can be seen that angular momentum is independent of the point about which it is measured.