Two objects have masses of #22 MG# and #23 MG#. How much does the gravitational potential energy between the objects change if the distance between them changes from #25 m# to #7 m#?

Please let me know the answer.... Thank you

1 Answer
May 5, 2017

#-0.0035J#, rounded to four decimal places

Explanation:

Gravitational Potential energy between two bodies of mass #M_1and M_2# with distance between their centers being #r# is given as

#U=-G(M_1M_2)/r#
where #G# is Universal Gravitational constant #=6.67408 xx 10^-11 m^3 kg^-1 s^-2#.
#-ve# sign shows that it is bound system.

#DeltaU=U_"final"-U_"initial"#
Inserting given values we get
#DeltaU=-G(M_1M_2)/7-(-G(M_1M_2)/25)#
#DeltaU=-G(M_1M_2)(1/7-1/25)#
#DeltaU=-6.67408 xx 10^-11(22xx10^3xx23xx10^3)(18/175)#
#DeltaU=-0.0035J#, rounded to four decimal places