Two objects have masses of 42 MG42MG and 25 MG25MG. How much does the gravitational potential energy between the objects change if the distance between them changes from 48 m48m to 15 m15m?

1 Answer
Feb 27, 2018

The change in gravitational potential energy is =321*10^-5J=321105J

Explanation:

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

So the units are J, "Joules"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=42MG=42*10^6g=42*10^3kg

The mass is M_2=25MG=25*10^6g=25*10^3kg

The distance between the centers is =Rm

The distance R_1=48m

The distance R_2=15m

Therefore,

Phi_1=(-G*(42*10^3*25*10^3)/48)

Phi_2=(-G*(42*10^3*25*10^3)/15)

So,

Phi_1-Phi_2=(-G*(42*10^3*25*10^3)/48)-(-G*(42*10^3*25*10^3)/15)

=42*25*10^6*6.67*10^-11(1/15-1/48)

=321*10^-5J