Amolecule of dna (deoxyribonucleic acid is 2.04 urm long. the ends of the molecule become singly ionized: negative on one end, positive on the other. the helical molecule acts like a spring and compresses 1.29% upon becoming charged. determine the effective spring constant of the molecule 16e9 x your answer cannot be understood or graded. more information n/m

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

What is the name of the perceived change in a sound wave’s frequency due to motion between the observer and the sound source?

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.