Unknown macro: {latex}
\large
$$
V =
Unknown macro: {Q over A}
$$
Unknown macro: {latex}
\large
$$
v_z = {1 \over {4\mu }}\left( {{
Unknown macro: {partial p}
\over
Unknown macro: {partial z}
}} \right)\left(
Unknown macro: {r^2 - R^2 }
\right)
$$