Can somebody give me hints to solve the following question?
I need to find the closed surface integral (using divergence theorem) of
$$\oint \vec{r} (\vec{a} \cdot \vec{n}) da$$
where $\vec{n}$ is the outward pointing unit vector of the surface S aroud the volume V and $\vec{r}$ is the radius vector and $\vec{a}$ is a constant vector
Thanks.