Calculate the gravitational force in mN between a 70 kg pers

Calculate the gravitational force (in mN) between a 70 kg person and the moon in two different configurations: The particle is on the side of the earth facing the moon The particle is on the opposite side of the earth... farthest away from the moon Compare the results by determining the percent difference: between the two forces Model all distances measured \"center to center\" and spherical mass distributions:

Solution

gravitation force F =GMm/r^2

a)F=GM_em/r_e^2 - GM_mm/(d-r_e)^2 = 687.03 -2.59*10^-3 = 687.027 N

b)F=GM_em/r_e^2 +GM_mm/(d+r_e)^2 = 687.03 + 2.42*10^-3 =687.032 N

c) percent difference=( 5.42*10^-3/687.03)*100% = 7.89*10^-4 %