The vectors $$\overrightarrow A $$ and $$\overrightarrow B $$ are such that $$\left| {\overrightarrow A + \overrightarrow B } \right| = \left| {\overrightarrow A - \overrightarrow B } \right|.$$ The angle between the two vectors is

Two boys are standing at the ends A and B of a ground where AB = a. The boy at B starts running in a direction perpendicular to AB with velocity v₁. The boy at A starts running simultaneously with velocity v and catches the other in a time t, where t is

If the angle between the vectors $$\overrightarrow A $$ and $$\overrightarrow B $$ is $$\theta $$, the value of the product $$\left( {\overrightarrow B \times \overrightarrow A } \right).\overrightarrow A $$ is equal to

If a vector $$2\widehat i + 3\widehat j + 8\widehat k$$ is perpendicular to the vector $$4\widehat j - 4\widehat i + \alpha \widehat k,$$ then the value of $$\alpha $$ is