Mrs. Baxter often holds a question-and-answer session with students during the class period. The Q&A session reinforces the knowledge that students have just learned, and sometimes introduces related content that will be covered next in class. What part of lesson planning does this Q&A session serve?

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?