Consider a spherical planet of uniform density rho. The distance from the planet's center to its surface (i.e., the planet's radius) is R_p. An object is located a distance R from the center of the planet, where R < R_p. (The object is located inside of the planet.)
a). Rewrite your result for g(R) in terms of g_p, the gravitational acceleration at the surface of the planet, times a function of R.
Express your answer in terms of g_p, R, and R_p.
It finds the expression for the gravitational acceleration at the surface of the planet.