Two small masses that are 10.0 cm apart attract each other with a force of 10.0 n. when they are 5.0 cm apart, these masses will attract each other with what force?

show work : )

We know, force is indirectly proportional to square of distance
F directly proportional 1/r²

You halved the distance [ from 10 to 5 ] 

New Force with 5 cm would be: = F'
F' = 1/(r/2)² = 4/r² = 4.F    [ As we have: F = 1/r²]
F' = 4F
F' = 4×10 = 40 N

In short, Your Answer would be 40 Newtons

Hope this helps!

The rocks expand when there hot/warm  and contract when they are cold.