Question

Two objects have masses of `42 MG` and `26 MG`. How much does the gravitational potential energy between the objects change if the distance between them changes from `8 m` to `9 m`?

Answer 1

We will use the formula `U=-G(Mm)/r`

Explanation:

We will first calculate the potential energy at 8m

`U_1=-(6.67*10^(-11)*42*26*10^6)/8=-0.009`Joules

`U_2=-(6.67*10^(-11)*42*26*10^6)/9=-0.008`Joules

so `ΔU=U_2-U_1=0.001`Joules

the change is positive because the distance gets bigger

(I assumed MG is megagrams.)