Two objects have masses of #9 MG# and #5 MG#. How much does the gravitational potential energy between the objects change if the distance between them changes from #24 m# to #48 m#?

1 Answer
Apr 6, 2018

The gravitational energy will change by #=0.9375*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=9MG=9*10^6g=9*10^3kg#

The mass is #M_2=5MG=5*10^6g=5*10^3kg#

The distance between the centers is #=Rm#

The distance #R_1=24m#

The distance #R_2=48m#

Therefore,

#Phi_1=(-G*(9*10^3*5*10^3)/24)#

#Phi_2=(-G*(9*10^3*5*10^3)/48)#

So,

#Phi_1-Phi_2=(-G*(9*10^3*5*10^3)/24)-(-G*(9*10^3*5*10^3)/48)#

#=9*5*10^6*6.67*10^-11(1/48-1/24)#

#=-0.9375*10^-5J#