Two objects have masses of 3 MG and 15 MG. How much does the gravitational potential energy between the objects change if the distance between them changes from 130 m to 24 m?

1 Answer
Feb 25, 2018

The change in gravitational potential energy is =10.2*10^-5J

Explanation:

Gravitational potential is the potential energy per kilogram at a point in a field.

So the units are J, "Joules"

Phi=-G(M_1M_2)/R

The gravitational universal constant is

G=6.67*10^-11Nm^2kg^-2

The masses causing the field is =M_1 kg and =M_2 kg

The mass is M_1=3MG=3*10^6g=3*10^3kg

The mass is M_2=15MG=15*10^6g=15*10^3kg

The distance between the centers is =Rm

The distance R_1=130m

The distance R_2=24m

Therefore,

Phi_1=(-G*(3*10^3*15*10^3)/130)

Phi_2=(-G*(3*10^3*15*10^3)/24)

So,

Phi_1-Phi_2=(-G*(3*10^3*15*10^3)/130)-(-G*(3*10^3*15*10^3)/24)

=3*15*10^6*6.67*10^-11(1/24-1/130)

=10.2*10^-5J