1. The problem statement, all variables and given/known data A positively charged particle (9.35pC) is suspended in equilibrium in an electric field between two horizontal parallel plates with opposite charges. Each one of the square plates has a charge of 5.5x10^-5C; and are separated by 6.25mm and their sides are 11cm long what is the mass of the particle? 2. Relevant equations E=kq/r^2 n=q/qp idk... 3. The attempt at a solution first i divided the charge of the particle by the elemental charge 9.35x10^-12/1.602x^-19 i got 58364544 then i multiplied this number by a protons mass 58364544*(1.673x^-27) i got 9.764x10^-20 the book says the answer is 4.9x10^-4 soo confused!