9. An alien observer is located in the disk of a spiral galaxy at a distance of Ro = 10 kpc from the center of the galaxy. The galaxy has a flat rotation curve with a circular velocity of 0 = Ksirs = 200 km s-!. The alien observes a star that has a radial velocity & =-20 km s-1 and is located at galactic longitude {= 150°. Assuming that both the star and the alien observer are on perfectly circular orbits around the center of the galaxy, calculate both the distance from the center of the galaxy to the star (R) and the distance from the alien observer to the star (d). You will want to use the equations v, = [N(R) – N(R.)]R, sin(f) and N(R) = ©/R.« In order to find d, you will need to use the Law of Cosines and an appropriate figure. %3D

9. An alien observer is located in the disk of a spiral galaxy at a distance of Ro = 10 kpc from the center of the galaxy. The galaxy has a flat rotation curve with a circular velocity of 0 = Ksirs = 200 km s-!. The alien observes a star that has a radial velocity & =-20 km s-1 and is located at galactic longitude {= 150°. Assuming that both the star and the alien observer are on perfectly circular orbits around the center of the galaxy, calculate both the distance from the center of the galaxy to the star (R) and the distance from the alien observer to the star (d). You will want to use the equations v, = [N(R) – N(R.)]R, sin(f) and N(R) = ©/R.« In order to find d, you will need to use the Law of Cosines and an appropriate figure. %3D