A particle is moving uniformly along a straight line as shown in the figure. During the motion of
the particle from A to B, the angular momentum of the particle about 'O'

Angular momentum L=mvr where r is the perpendicular distance between velocity and reference point Here since the line AB is straight, there would only 1 perpendicular distance from reference point i.e OA So, Angular momentum at A =mvr Angular momentum at P =mvr Angular momentum at B =mvr Since, perpendicular distance between the line AB and O will always be R So all the points lying on the line AB will have same angular momentum equals to mvr.