Two particles each of mass `m` and speed `v`, travel in opposite direction along parallel lines separated by a distance d. Show that the vector angular momentum of this system of particles is the same about any point taken as origin.

Explanation

Angular momentum about A, `L_(A)=mvxx0+mvxxd=mvd`
Angular momentum about B, `L_(B)=mv xx d+mvxx0=mvd`
Angular momentum about C,
`L_(c )=mvxx y+mv xx(d-y)=mvd`
In all the three cases, the direction of angular momentum is the same.
`therefore " " vec(L_(A))=vec(L_(B))=vec(L_(C ))`