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.