A solid uniform sphere has a mass of $8\mathrm{.}00104$ kg and a radius of $1\mathrm{.}1$ m$.($Use the following as necessary: r and m$.$ Assume SI units. Do not enter units in your answers.$)$

$($a$)$ What is the magnitude of the gravitational force due to the sphere on a particle of mass m located at a distance of $1\mathrm{.}5$ m from the center of the sphere?

F $=$

N

$($b$)$ What if it is $0\mathrm{.}8$ m from the center of the sphere?

F $=$

N

$($c$)$ Write a general expression for the magnitude of the gravitational force on the particle at a distance r $1\mathrm{.}1$ m from the center of the sphere.

F $=$

N