The Hawaiian islands formed when molten material erupted from the ocean floor. As the lava flowed out, cooled, and hardened, massive rocks formed. These rocks have a very fine texture and tiny crystals that cannot be seen with the naked eye. These massive rocks formed into the islands that are present today. What type of igneous rock are the Hawaiian islands?

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?