Two objects have masses of #33# #Mg# and #18# #Mg#. How much does the gravitational potential energy between the objects change if the distance between them changes from #81# # m# to #3# #m#?

1 Answer
Aug 7, 2017

Use Newtons gravitational law for celestial bodies: #F = G\(m_1 m_2) / r^2#.

G is the gravitational constant, equaling 6.67408 × #10^-11 N*m^2/(kg)^2#

The masses #m_1# and #m_2# are the masses you mentioned.

The #r^2# is 3 respectively 81 meters. (It is mentioned as #r_2# because it is meant to be a radius, which the same as the distance from the center of an object to the center of another)

Now calculate the forces at both distances, and substract.