Two point charges, initially 2 cm apart, are moved to a distance of 10 cm apart. By what factor do the resulting electric and gravitational forces between them change?

I know the answer.....it is 1/25
I need help on how do u get that answer:D

Question

Two point charges, initially 2 cm apart, are moved to a distance of 10 cm apart. By what factor do the resulting electric and gravitational forces between them change?

I know the answer.....it is 1/25
I need help on how do u get that answer:D

anonymous · Answer

remember to use 1 c for a point charge or test charge

anonymous · Answer

went from   
8.9*10^9/.02^2

to

8.9*10^9/.1^2

awesome781 · Answer

Oh...... thank you:D

anonymous · Answer

idk if i am doing it right but i get by a factor of 25 :P  idk tho

awesome781 · Answer

Yes ......I get 25....based on ur method...

anonymous · Answer

How so? i think yo uwould also need to take a sampe using one kilo and G :)

anonymous · Answer

but i predict it wont matter

anonymous · Answer

6.673*10^-11    is G   

It wont make no difference to  K being 

8.9*10^9

anonymous · Answer

how you get cubed?

awesome781 · Answer

So we got 25 how do we get 1/25 then?

anonymous · Answer

8.9*10^9/.02^2

---------------           or flip it       either way you get 1/25 or 25 :D

8.9*10^9/.1^2

awesome781 · Answer

You are the best @timo86m ......^_^