Answer: Lets consider an arbitrary time when the point A is at a distance of x from point B.
Taking point B’s velocity component along the direction of A velocity, the two
points are coming closer at a speed given by
Integrating this equation,
where τis the required time. This gives:
Also, when the points meet, the two points must have traveled an equal
distance along the direction in which point B travels. Thus,
I.e. the two points will meet after a time given by .