A single infinite sheet of charge is aligned on the y axis. A point charge of -6.4 micro-Coulombs is placed to the right (in positive x direction) on a string. It swings to an angle of 28.8 degrees with the vertical before coming to equilibrium (taking into account weight - do not ignore weight). If the mass of the charge is 3 kg, what is the surface charge density of sheet of charge in micro-Coulombs/m2?