Question

If I have two objects charged, one on a insulated thread and one stationary, and I have one distances and an acceleration and I double the distance, I want to find out the acceleration, what formula do I use?
( the distance is halved and I need to find out the magnitude of the acceleration )

Answer 1

Coulomb’s Law
F1=k•q1•q2/r1²
F2 = k•q1•q2/r2²,
Newton’s 2 Law
a1=F1/m = k•q1•q2/r1²•m
a2 =F2/m= k•q1•q2/r2²•m

a1/a2 ={k•q1•q2/r1²•m}/{k•q1•q2/r2²•m} =
=(r2/r1)²