The two strands of the helix-shaped DNA molecule are held together by electrostatic forces as shown in the Figure 16-44 in the textbook. Assume that the net average charge (due to electron sharing) indicated on H and N atoms is 0.2e and on the indicated C and O atoms is 0.4e. Assume also that atoms on each molecule are separated by 1.0×10⁻¹⁰m.

A) Estimate the net force between a thymine and an adenine. For each bond (red dots) consider only the three atoms in a line (two atoms on one molecule, one atom on the other).
B) Estimate the net force between a cytosine and a guanine.
C) Estimate the total force for a DNA molecule containing 105 pairs of such molecules.