If the angle between the vector $\vec{A}$ and $(\vec{B} \times \vec{A}) \cdot \vec{A}$ is $\theta$, the…
If the angle between the vector $\vec{A}$ and $(\vec{B} \times \vec{A}) \cdot \vec{A}$ is $\theta$, the value of the product $(\vec{B} \times \vec{A}) \cdot \vec{A}$ is equal to:
$B A^2 \sin \theta$
$B A^2 \cos \theta$
$B A^2 \sin \theta \cos \theta$
zero
Solution
$(\vec{B} \times \vec{A}) \vec{A}=(B A \sin \theta)(\vec{n} \cdot \vec{A})=0$
Since $n$ is perpendicular to both $\vec{A}$ and $\vec{B}$.