Consider a planet with a uniform density of 3.9 g/cm3 and a radius of 6230 km. What is the gravitational force felt by a 25 -kg block located on the surface of this planet?

Answer 1

3.9 g/cm^3 * 10^-3 kg/g * (10^2)^3 cm^3/m^3 = 3.9 * 10^3 kg/m^3 density
R = radius of planet = 6.230 * 10^6 meters
mass of planet = M = 3.9 * 10^3 kg/m^3 * (4/3) pi R^3
G = 6.67 * 10^-11 Nm^2/kg^2
F = G m M /R^2
= 6.67 * 10^-11 * 25 * 3.9 * 10^3 * (4/3) pi * 6.230 * 10^6