A small sphere with mass $2\mathrm{.}00{10}^{-3}kg$ and charge $4\mathrm{.}80{10}^{-8}C$ hangs from a thread near a very large, charged insulating sheet. The charge density on the surface of the sheet is uniform and equal to $-2\mathrm{.}20{10}^{-9}\frac{C}{m^2}.$ Find the angle of the thread. $(15\%)$