A flask has a base of radius 12 cm and narrows to a neck of radius 6 cm. It’s filled to the base of the neck with water. If 5.5x10-4 m3 of additional water is poured into the flask, by how much does the force of the water on the base increase?

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?