Problem 3.354

A point charge $q$ moves with a non-relativistic velocity $\mathrm{v}=$ const. Applying the theorem for the circulation of the vector $\mathbf{H}$ around the dotted circle shown in Fig. $3.97,$ find $H$ at the point $A$ as a function of a radius vector $\mathbf{r}$ and velocity $\mathbf{v}$ of the charge.