1) 3 equal positive charges are fixed to the corners - one on each corner - of an equilateral triangle of side 1 m. The triangle is sitting on one of its sides. Each q has a value of one coulomb. Find the electric field at the center of the triangle. 2) A positive charge of 18nC is evenly distributed along a straight rod of length 4.0 m that is bent into a circular arc with a radius of 2.0 m. Find the magnitude of the electric field at the center of curvature of the arc? 3) Two infinite-plane nonconducting thin sheets of uniform surface 13?C/m2 and _9?C/m2 are parallel to each other and 0.2 m apart. What are the electric fields between the two sheets and outside of them?