Question

A thin nonconducting rod is bent to form a semi-circle of radius R. A charge Q is uniformly distributed along the upper half and a charge -Q is uniformly distributed along the lower half, as shown int he sketch at the right.find E vector at P, the center of the semi-circle. the semi circle looks like that, plus at the top and minuses at the bottom. P is the center and the radius arrow point to the minuses