Two charges are separated by a certain distance, the magnitude of each charge is doubled, the force on each charge is __ ?

Your answer is 1.5 hope i  

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other

Answerinternal combustion engine fuel;