Connie flew from Phoenix to Flagstaff, a distance of 180 miles at a constant speed of 180 miles per hour. She the returned to the same airport at a constant speed of 90. miles per hour. a.) What was Connie's average speed in miles/hour?

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