A molecule of DNA (deoxyribonucleic acid) lies along a straight line. It is 2.778 µm long. The ends of the molecule become singly ionized; negative on one end, positive on the other. The helical molecule acts as a spring and compresses 1% upon becoming charged. Determine the effective spring constant of the molecule. Take into account the compressed length when calculating the distance between the ends of the molecule. The Coulomb constant is 8.99 × 109 N · m2 /C 2 . Answer in units of N/m.