The electric force between two charges increases when A) both charges become negative
B) both charges become positive
C) the charges get closer together
D) the charges get further apart

Panel bc in fig. p2.76 is semi-circular, with the 3 meter radius and horizontal straight edge through point b. compute (a) the hydrostatic force of the water on the panel, (b) its center of pressure, and (c) the moment of this force about point b. assume atmospheric pressure on the dry side of the panel