Answer:
Explanation:
Given
Force of repulsion between two charge particle is given by force F
Electrostatic force is given by

where
and
is the charges of particle
r=distance between charge particle
when charges are doubled and distance is reduced to half
i.e. q become 2 q and r becomes 0.5 r



The coin would probably slowly slide down whichever end it is closer to, weigh down the end of the paper, and fall off. It kinda depends on how you hold the paper though, because if it is directly in middle, and you hold it on both ends, it will stay on the paper.