A particle is projected with initial speed of $V_0$ and angle of $ \theta $ . Find the horizontal displacement when its velocity is perpendicular to initial velocity.
$ \vec V_0 = V_0cosθ \hat i + V_0 sinθ \hat j$ $ \vec V = V_0 cosθ \hat i + (V_0sm \theta – gt) \hat j$ $ \vec V_0 . \vec V = 0 $ $ \therefore t = { V_0 \over gsin \theta } $ Now find x