Kaleigh is riding her bike on a Saturday Afternoon, She rides 22 km south, then turns west and rides 8 km. She then turns north and rides 3 km. Calculate her displacement from starting point to end point be sure to include the direction.

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?