The plastic bar shown in Figure has a total charge of -Q, and is bent with an angle of 120 degrees and a radius of r. Place the axis of symmetry of the bar as the x-axis and place the origin of the coordinate system as the origin of the curvature. Mark the vector of the electric field at point P as r and Q. Use the result of the integration below. Plastic rod of charge -Q 60 60 cose do = N3 P. 60