A 72-kg skydiver is falling from a high altitude. At an instant during the fall, the skydiver encounters an air resistance force of 540 Newtons. Determine the acceleration (in m/s2) of the skydiver at this instant. (Hint: you should find the weight of the skydiver first, and then calculate the net force and acceleration)

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system