Electric force between objects that are in brief contact

[Jabababa]

Homework Statement

Two small charged objects of the same mass and volume are brought into brief contact with each other. If the initial charges on the two objects are -3.00 x10^-6 and -1.50 x10^-6, what is the electric force between the objects when they are separated to a distance of 0.500m after contact?

The answer is 1.82 x10^1 N

Homework Equations

F=KQ1Q2/r^2

The Attempt at a Solution

I thought it is just plug in the numbers but i get a different answer. So is there anything that goes on when they are in contact?

F= (9.0x10^9)(-3.00x10^-6)(-1.50x10^-6)/(0.500)^2
=0.162N

 

[ap123]

The important thing here is that they are brought into contact first.
What changes does that cause?

 

[Jabababa]

im not really sure...

umm their initial distance? Or it will have to be something to do with their charge (transfer of electro maybe)?

 

[tia89]

I think the objects you have are conductors?? What happens in this case?? And anyway are you sure the result is not 1.82x10^(-1)?? (you put 10^1)...

 

[ap123]

I think the objects you have are conductors??

I think you have to assume they're conductors, since it gives the right answer :)

And anyway are you sure the result is not 1.82x10^(-1)??

Yes - this is the answer I got.

Jabababa - When you put two unequally charged conductors in contact, what happens to the charges on them?

 

[tia89]

I think you have to assume they're conductors, since it gives the right answer :)

Just as I thought