Question

Two objects have masses of `42 MG` and `48 MG`. How much does the gravitational potential energy between the objects change if the distance between them changes from `21 m` to `15 m`?

Answer 1

`W_1,_2= -2,56 *10^-3J`
`W_1,_2=-GMm( 1/r_2-1/r_1)`
below zero because the objects , are closer than before.

Explanation:

`W_1,_2=-GMm( 1/r_2-1/r_1)`
`G=6,67*10^-11 Nm^2/(kg)^2`
`r_1=21m`
`r_2=15m`
`M=48 MG=48000kg`
`m=42 MG=42000kg`
`W_1,_2= -2,56 *10^-3J`