Describes the orbits of stars within most elliptical galaxies?

I’ve been stuck on this for a while

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?

Elements in group viiia (also known as group 18, or the noble gases) have similar properties because they all have a. the same number of electron shells b. full octets c. the same number of valence electrons d. the same number of electrons needed to fill their octet