the main strenght is each person has a job and the weekness is they are poor
Answer:2155 J
Explanation:
Given
Change in Internal energy
i.e. decrease in Internal Energy
Heat added to system 
According First law for a system



Thus 2155 J of work is done by system
The force of gravity between two objects is:
F = G*m1*m2/r^2
So, it is dependent of the two masses and the distance between their centers of mass.