Question details:

question details:
a spere of matter, of mass m andradius a, has a concentric
cavity of radius b, as shownbelow.
a.) sketch a curve of thegravitational force f exerted by the
sphere on a particle of massm, located at a distance r from the
center of the sphere, as afunction of r in the range 0 < = r < =
infinity. consider r = 0, b, and and infinity in particular.
b.) sketch the correspondingcurve for the potential energy
u(r) of thesystem.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

snell's law

refractve index = sin incidence / sin refraction