A particle is projected at point A from an inclination plane with inclination angle `theta` as show

A particle is projected at point A from an inclination plane with inclination angle `theta` as shown in figure. The magnitude of projection velocity is `vecu` and its direction is perpendicular to the plane. After some time it passes from point B which is in the same horizontal level of A, with velocity `vecv`. Then the angle between `vecu and vecv` will be

`theta`