HELP!!!A question on electricity (electric field and electric potential) 1. The problem statement, all variables and given/known data Three point charges are located at the corners of an equilateral triangle as shown. http://s5.tinypic.com/2hdvalh.jpg a) Find the magnitude and direction of the electric field at P b) Find the magnitude and direction of the electric field at P(The potential at infinity is zero) c) What is the electric potential energy of a particle with charge 4 µC placed at P? d) If the mass of the particle is 7.0*10^-11kg, what minimum velocity muse it be given so that it can escape to infinity? 3. The attempt at a solution a)E=KQ/r^2 Etotal=(9*10^9x1*10^-6)/0.3^2+(9*10^9x2*10^-6)/0.3^2+(9*10^9x-2.5*10^-6)/0.52^2=216549.06 point up because the top point has the strongest charge (I am not sure whether I got the direction right or not) b)V=KQ/r Vtotal=(9*10^9x1*10^-6)/0.3+(9*10^9x2*10^-6)/0.3+(9*10^9x-2.5*10^-6)/0.52=46678.85 c)V=KQ1Q2/r Vtotal=(9*10^9x1*10^-6x4*10^-6)/0.3+(9*10^9x2*10^-6x4*10^-6)/0.3+(9*10^9x-2.5*10^-6x4*10^-6)/0.52=0.187 d)V=sqrt(2kQ/mr) m=mass Vtotal=sqrt((9*10^9x1*10^-6)/(7*10^-11x0.3))+sqrt((9*10^9x2*10^-6)/(7*10^-11x0.3))-sqrt((9*10^9x2.5*10^-6)/(7*10^-11x0.3))=35500654.39 For part d I don't really know how to solve for velocity after I got the voltage Even though I got the answer for all of them, but I don't think it is the right way to approach the problem, because the answers are either too big or too small Please help me with it. Thank you very much.