Elliptical, because the shape of the galaxy isn’t like the others. It is unique to its own and doesn’t have another to compare to
Downwards - from uphill towards the lowlands and eventually into the sea.
I believe this is it
The centripetal force is given by
F = mv^2 / r
When v' = v/2,
F' = mv'^2/r = m(v/2)^2/r = mv^2/4r = F/4.
So the centripetal force is divided by 4.