Question

A particle is projected at point A from an inclined plane with inclination angle $\theta$ as shown in figure. The magnitude of projection velocity is $\vec{u}$ 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 $\vec{v}$ . Then the angle between $\vec{u}$ and $\vec{v}$ will be

• A. $\theta$
• B. $2\theta$
• C. $\pi -2\theta$
• D. $90+\theta$

Answer 1

Answer: (C)

$\alpha$ is the required angle.



so $\alpha =180^{\circ }-2\theta$