Question

How much charge is needed to repel another charge of 9.9 x 10^-6 N when they are 200m apart? Please help meee I really can't understand Coulomb's Law : (

Answer 1

Answer:

The charge needed will be $q=6.6\: \mu C$

Step-by-step explanation:

The equation of the electric force is given by:

$F=k\frac{qQ}{r^{2}}$

We have the force $F = 9.9 10^{-6}\: N$  and the distance r = 200. k is the Coulomb constant. Q and q are the charges.

We assume we have the same charge of the particles,  so we have:

$q^{2}=\frac{Fr^{2}}{k}$

$q^{2}=\frac{9.9*10^{-6}200^{2}}{9*10^{9}}$

$q=6.6*10^{-6}\: C$

Therefore, the charge needed will be $q=6.6\: \mu C$

I hope it helps you!