Two objects have masses of 5 MG and 12 MG. How much does the gravitational potential energy between the objects change if the distance between them changes from 150 m to 270 m?

1 Answer
Mar 3, 2018

The change in gravitational potential energy is =1.19*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=5MG=5*10^6g=5*10^3kg

The mass is M_2=12MG=12*10^6g=12*10^3kg

The distance between the centers is =Rm

The distance R_1=150m

The distance R_2=270m

Therefore,

Phi_1=(-G*(5*10^3*12*10^3)/150)

Phi_2=(-G*(5*10^3*12*10^3)/270)

So,

Phi_1-Phi_2=(-G*(5*10^3*12*10^3)/150)-(-G*(5*10^3*12*10^3)/270)

=5*12*10^6*6.67*10^-11(1/270-1/150)

=-1.19*10^-5J