Question

A semicircle of radius a is in the first and second quadrants, with the center of curvature at the origin. Positive charge +Q is distributed uniformly around the left half of the semicircle, and negative charge −Q is distributed uniformly around the right half of the semicircle in the following figure

Answer 1

The charges are distributed along the semicircle with the left side having the charge of +Q and the right side having the charge of -Q. If what is asked is the net electrical force at the origin, then the answer is 0 since the charges are uniform on both sides.