J 3. A plastic disk of radius R = 64.0 cm is charged on one side with a uniform surface charge density 0 = 7.73 x 10'15C/m2, and then three quadrants of the disk are removed. The remaining quadrant is shown in Fig. 3. With V = 0 at infinity, what is the potential due to the remaining quadrant at point P, which is on the central axis of the original disk at distance D = 25.9 cm from the original center